There are at least 500 kinds of fish that generate (appreciate) amounts of electricity.
Tuyển Cộng tác viên Hoc24 nhiệm kì 26 tại đây: https://forms.gle/dK3zGK3LHFrgvTkJ6
Most students love school uniforms. IS / ARE (NOT) + V-3/ V-ED…PHẦN CÒN DƯ (BY + O)
--> School…………………………………………………………………………………..
They don’t sell frozen food at that shop.
--> Frozen FOOD ……… …………………….……………………………
We use electricity for all kinds of purposes.
--> Electricity…………………………………………………………………..
4. In Africa, people grow food on small farms.
--> Food ……………………………………………………………
People recycle old car tires to make shoes and floor coverings.
--> Old…………………………….…………………………….……………………………
They speak Chinese, English and Tamil in Malaysia. (IS / ARE + V-3 + …….)
---> Chinese, English and Tamil.............................................................................
7. Women usually wear Ao Dai on special occasions. ---> Ao Dai...................................
8. The zoo keepers feed the animals twice a day. --->The animals..................................
Most students love school uniforms. IS / ARE (NOT) + V-3/ V-ED…PHẦN CÒN DƯ (BY + O)
--> School………………uniforms are loved by most students…………………………………………………………………..
They don’t sell frozen food at that shop.
--> Frozen FOOD ……… …isn't sold at that shop.………………….……………………………
We use electricity for all kinds of purposes.
--> Electricity……………is used for all kinds of purposes.……………………………………………………..
4. In Africa, people grow food on small farms.
--> Food …………………is grown on small farms in africa.…………………………………………
People recycle old car tires to make shoes and floor coverings.
--> Old……………………car retires are recycled to make shoes and floor coverings.……….…………………………….……………………………
They speak Chinese, English and Tamil in Malaysia. (IS / ARE + V-3 + …….)
---> Chinese, English and Tamil.........................are spoken in Malaysia.....................................................
7. Women usually wear Ao Dai on special occasions. ---> Ao Dai.....................is usually worn on special occasions ............
8. The zoo keepers feed the animals twice a day. --->The animals.............are fed by the zoo keepers twice a day......................
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
The ability to conduct electricity is one of the key properties of a metal. Other solid material such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. The lost electrons are free to move in what are known as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.
An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the ‘lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow. Freshwater Aquarium Fish
Playlist Freshwater Aquarium Fish
Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor or electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.
By Helena Gillespie and Rob Gillespie. Science for Primary School Teacher. OUP
Salt in its solid state is not able to conduct electricity because .
A. it has free electrons
B. its charged ions can flow easily
C. it cannot create any charge ions
D. it charged ions are not free to move
Đáp án : D
Cuối đoạn 2: In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow.
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
The ability to conduct electricity is one of the key properties of a metal. Other solid material such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. The lost electrons are free to move in what are known as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.
An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the ‘lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow. Freshwater Aquarium Fish
Playlist Freshwater Aquarium Fish
Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor or electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.
By Helena Gillespie and Rob Gillespie. Science for Primary School Teacher. OUP
According to the passage, a metal can conduct electricity due to
A. the absence of free electrons
B. its atoms with a positive charge
C. the way its atoms bond together
D. the loss of one electron in the core of its atoms
Đáp án : C
Từ cuối dòng 3: The ability of metals to conduct electricity is due to how their atoms bond together (= bởi cách các phân tử gắn kết với nhau)
Describe a visitor attraction that you know, using at least three of the adjectives in exercise 1.
Old Town Square in Prague is very impressive. There are lots of historic buildings, but it's a bit touristy.
The ancient town of Hoi An in Vietnam is a beautiful and historic attraction that draws many visitors each year. The town has well-preserved buildings that showcase traditional Vietnamese architecture and culture, making it an impressive destination for tourists. However, due to its popularity, it can be quite crowded and expensive, especially during peak travel seasons. Despite the crowds, the town's charming atmosphere and rich history make it a must-visit attraction for those traveling to Vietnam.
(Phố cổ Hội An ở Việt Nam là một điểm tham quan đẹp và lịch sử thu hút nhiều du khách mỗi năm. Thị trấn có các tòa nhà được bảo tồn tốt thể hiện kiến trúc và văn hóa truyền thống của Việt Nam, khiến nơi đây trở thành một điểm đến ấn tượng đối với khách du lịch. Tuy nhiên, do sự phổ biến của nó, nó có thể khá đông đúc và đắt đỏ, đặc biệt là trong mùa du lịch cao điểm. Bất chấp sự đông đúc, bầu không khí quyến rũ và lịch sử phong phú của thị trấn khiến nơi đây trở thành điểm tham quan không thể bỏ qua đối với những ai đi du lịch Việt Nam.)
there are 10 persons attending a meeting, each of them knowing at least 5 other persons.Prove that it is possible to arrange 4 persons into a 4-seat table such that each of them sits next to 2 persons they know.
có 10 người tham dự cuộc họp, mỗi người đều biết ít nhất 5 người khác. Cố gắng sắp xếp 4 người vào một bảng 4 chỗ để mỗi người ngồi bên cạnh 2 người họ biết
mẹ đi chợ mua một số táo rồi xếp vào các đĩa nếu xếp mỗi đĩa 4 quả thì vừa hết số táo , nếu xếp mỗi đĩa 5 quả thì cung vừa hết số táo đó hỏi mẹ mua bao nhiêu quả táo , biết số táo mẹ mua ít hơn 25 quả . mình cần gấp câu trả lời
mik cần lời giải cơ mik ko biết làm sao để xếp
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
The ability to conduct electricity is one of the key properties of a metal. Other solid material such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. The lost electrons are free to move in what are known as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.
An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the ‘lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow. Freshwater Aquarium Fish
Playlist Freshwater Aquarium Fish
Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor or electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.
By Helena Gillespie and Rob Gillespie. Science for Primary School Teacher. OUP
Which of the following could best serve as the title of the passage?
A. Electrical Energy
B. Electrical Devices
C. Electrical Insulators
D. Electrical Conductivity
Đáp án : D
Cả bài nói về khả năng dẫn điện, từ đặc tính dẫn điện của kim loại, các chất dẫn điện kém như nước, tới các chất cách điện
Combinatorics
21. 15 students join a competition. Only top 5 students can be promoted to next round. How many different way(s) of promotion advance is / are there?
Different way: Cách khác nhau.
22. It is known that there are 8 classes of grade 5 in a primary school. At least how many students are there in grade 5 to ensure there exist 41 students in the same class?
At least: Ít nhất; Ensure: Chắc chắn; Exist: Tồn tại.
23. Choose 3 digits from 1, 2, 3, 4, 6, 8 and 0 to form 3-digit numbers. How many even number(s) greater than 300 is / are there? (The repetition of digits is not allowed)
Digit: Chữ số; 3-digit number: Số có 3 chữ số; Even number: Số chẵn; Greater than: Lớn hơn; Repetition of digits is not allowed: Các chữ số không được lặp lại.
24. A flight of stairs has 10 steps. Peter can go up for 1 step, 2 steps or 3 steps each time. How many way(s) is / are there for Peter to go up the stairs?
Step: Bước; Way: Cách.
25. Numbers are drawn from 80 integers 20 to 99. At least how many number(s) is / are drawn at random to ensure that there are two numbers whose sum is 85?
Integer: Số nguyên; At least: Ít nhất; Random: Ngẫu nhiên; Ensure: Chắc chắn; Sum: Tổng.
~ End of Paper ~
là seo pạn?mik hem hỉu??????????????????????
Đọc cái bài mà mún trầm kẻm!
Combinatorics
21. 15 students join a competition. Only top 5 students can be promoted to next round. How many different way(s) of promotion advance is / are there?
Different way: Cách khác nhau.
22. It is known that there are 8 classes of grade 5 in a primary school. At least how many students are there in grade 5 to ensure there exist 41 students in the same class?
At least: Ít nhất; Ensure: Chắc chắn; Exist: Tồn tại.
23. Choose 3 digits from 1, 2, 3, 4, 6, 8 and 0 to form 3-digit numbers. How many even number(s) greater than 300 is / are there? (The repetition of digits is not allowed)
Digit: Chữ số; 3-digit number: Số có 3 chữ số; Even number: Số chẵn; Greater than: Lớn hơn; Repetition of digits is not allowed: Các chữ số không được lặp lại.
24. A flight of stairs has 10 steps. Peter can go up for 1 step, 2 steps or 3 steps each time. How many way(s) is / are there for Peter to go up the stairs?
Step: Bước; Way: Cách.
25. Numbers are drawn from 80 integers 20 to 99. At least how many number(s) is / are drawn at random to ensure that there are two numbers whose sum is 85?
Integer: Số nguyên; At least: Ít nhất; Random: Ngẫu nhiên; Ensure: Chắc chắn; Sum: Tổng.
~ End of Paper ~
Combinatorics
21. 15 students join a competition. Only top 5 students can be promoted to next round. How many different way(s) of promotion advance is / are there?
Different way: Cách khác nhau.
22. It is known that there are 8 classes of grade 5 in a primary school. At least how many students are there in grade 5 to ensure there exist 41 students in the same class?
At least: Ít nhất; Ensure: Chắc chắn; Exist: Tồn tại.
23. Choose 3 digits from 1, 2, 3, 4, 6, 8 and 0 to form 3-digit numbers. How many even number(s) greater than 300 is / are there? (The repetition of digits is not allowed)
Digit: Chữ số; 3-digit number: Số có 3 chữ số; Even number: Số chẵn; Greater than: Lớn hơn; Repetition of digits is not allowed: Các chữ số không được lặp lại.
24. A flight of stairs has 10 steps. Peter can go up for 1 step, 2 steps or 3 steps each time. How many way(s) is / are there for Peter to go up the stairs?
Step: Bước; Way: Cách.
25. Numbers are drawn from 80 integers 20 to 99. At least how many number(s) is / are drawn at random to ensure that there are two numbers whose sum is 85?
Integer: Số nguyên; At least: Ít nhất; Random: Ngẫu nhiên; Ensure: Chắc chắn; Sum: Tổng.
~ End of Paper ~
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions
The ability to conduct electricity is one of the key properties of a metal. Other solid material such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. The lost electrons are free to move in what are known as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.
An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the ‘lead’ of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow. Freshwater Aquarium Fish
Playlist Freshwater Aquarium Fish
Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor or electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.
By Helena Gillespie and Rob Gillespie. Science for Primary School Teacher. OUP
The atoms of a metal can bond together because
A. the lost electrons cannot move freely in the sea of electrons
B. electrons can flow in a single direction
C. they lose all of electrons
D. negatively charged electrons attract positive ions
Đáp án : D
Từ dòng 4: In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. ... Since the electrons are negatively charged they attract the ions and this is what keeps the structure together. -> để gắn kết với nhau, các nguyên tử kim loại mất ít nhất một trong những electron ngoài cùng, khiến cho nguyên tử mang điện tích dương, trở thành các ion thực sự… vì các electron mang điện tích âm, chúng hút những ion và điều này tạo nên cấu trúc bền vững -----> các nguyên tử gắn kết vì các electron mang điện tích âm hút ion dương