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☺☺☺ Xin chào cả nhà, ☺☺☺☘ ☘ ☘ Cuộc thi Olympic Tiếng Anh VOEC mùa này đã kết thúc với rất nhiều điều thú vị. Vui có, buồn có, hăng hái và chán nản, đủ cả. Song, cô tin chắc rằng điều quan trọng nhất còn đọng lại là những bài học đáng quý về sự nỗ lực của các thành viên, những cơ hội rèn luyện ngoại ngữ và được giao lưu cùng nhau; đúng không các em?☘ ☘ ☘ Dưới đây là phần tổng hợp những bài viết nổi bật nhất sau cuộc thi, cô biết còn rất nhiều bài hay của các bạn khác nữa; nhưng những bài dưới đây...
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Trương Ngọc Ánh
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Nguyễn Thị Thương Hoài
27 tháng 8 2023 lúc 19:45

900 : 20 = 45

500 : 40 = \(\dfrac{25}{2}\)

600: 30 = 20

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Nguyễn Xuân Thành
27 tháng 8 2023 lúc 19:45

\(900:20=45\)

\(500:40=12,5\)

\(600:30=20\)

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Trương Ngọc Ánh
27 tháng 8 2023 lúc 19:46

mình cảm ơn 

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Hung Nguyen Cong
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ILoveMath
16 tháng 11 2021 lúc 21:43

\(a,B=\left\{1;2;3;...;17\right\}\\ b,C=\left\{10;11;...;17\right\}\)

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Nguyễn Ngọc Khánh Huyền
16 tháng 11 2021 lúc 21:43

a.B={x ∈ N*|x < 18}
→ B={1;2;3;4;5;6;7;...;17}
 b.C={x ∈ N|10 ≤ x < 18}
→ C={10;11;12;13;14;15;16;17}
 

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Nguyễn Lê Phước Thịnh
16 tháng 11 2021 lúc 21:44

b: B={1;2;3;...;17}

c: C={10;11;...;17}

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Huỳnh Thị Mỹ Hạnh
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Sunn
17 tháng 12 2021 lúc 13:30

Ex: I have three lessons today. It's math, literature, Vietnamese.

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tuấn anh
17 tháng 12 2021 lúc 13:31

I do not know

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qlamm
17 tháng 12 2021 lúc 13:38

I have 7 lessons. It's 2 Math periods, Chemistry, Literature, 2 English periods, Biological

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nguyễn bảo an
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Kiều Vũ Linh
26 tháng 9 2023 lúc 20:47

S = 1 + 2 + 2² + 2³ + ... + 2²⁰¹⁷

2S = 2 + 2² + 2³ + 2⁴ + ... + 2²⁰¹⁸

S = 2S - S

= (2 + 2² + 2³ + 2⁴ + ... + 2²⁰¹⁸) - (1 + 2 + 2² + 2³ + ... + 2²⁰¹⁷)

= 2²⁰¹⁸ - 1

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Ngô Hải Nam
26 tháng 9 2023 lúc 20:49

`S=1+2+2^2+2^3+...+2^2017`

`2S=2+2^2+2^3+2^4+...+2^2018`

`2S-S=(2+2^2+2^3+2^4+...+2^2018)-(1+2+2^2+2^3+...+2^2017)`

`S=2^2018 -1`

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『Kuroba ム Tsuki Ryoo...
26 tháng 9 2023 lúc 20:51

`#3107`

\(S=1+2+2^2+2^3+...+2^{2017}\\ 2S=2+2^3+2^4+...+2^{2018}\)

\(2S-S=\left(2+2^2+2^3+2^4+...+2^{2018}\right)-\left(1+2+2^2+2^3+...+2^{2017}\right)\)

\(S=2+2^2+2^3+2^4+...+2^{2018}-1-2-2^2-2^3-...2^{2017}\)

\(S=2^{2018}-1\)

Vậy, \(S=2^{2018}-1.\)

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Nguyễn Linh
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Vũ Minh Tuấn
18 tháng 10 2019 lúc 12:21

Tham khảo:

I. Choose the best answer by circling A, B, C or D:

1. - “What would you like to drink now?” - “_______________.”

A. No, thanks B. Yes, please

C. I like to do nothing D. Orange juice, please

2. All of us enjoy _______ to classical music.

A. listen B. listens C. listening D. listened

3. She worked very hard, _______she passed all her exams.

A. because B. and C. so D. but

4. Hoa looks red. She was outdoors yesterday. Perhaps she has _______

A. flu B. sunburn C. spots D. stomachache

5. My family has decided to use _________ electricity by using more solar energy instead.

A. more B. less C. much D. fewer

6. I ............... playing board games interesting because I can play them with my friends.

A. find B. think C. say D. tell

7. -“ Would you like me to turn off your computer?

- “ ______________. I’ll do it myself”

A. No, thanks B. Yes, please C. Don’t do it D. Of course

8. You like playing monopoly or chess, your hobby may be _______.

A. collecting things. B. playing sports

C. dancing D. board games

9. I …………….. Nha Trang when I was a child.

A. visit B. visited C. will visit D. have visited

10. He …………… to the USA so far.

A. is B. was C. will be D. has been

11. Americans eat a lot of junk food, ………….junk food causes obesity.

A. but B. and C. so D. because

12. Tim: I feel itchy and my nose is running. Doctor: ………………………..

A. Wash your hair more. B. I think you have the flu.

C. Drink more water. Eat less meat D. I think you have a stomachache.

13. Pick out the word whose main stress is placed differently from the others.

A. allergy B. headache C. temperature D. obesity

14. Choose the word that has the underlined part pronounced differently from the others.

A. cold B. curly C. ocean D. clothes

15. It is interesting _____________ tree leaves from different countries.

A. collecting B. to collect C. collect D. collects

16. My dad enjoys ________ his bike to work.

A. to ride B. ride C. rides D. riding

17. I love cooking, _________ my sister doesn’t.

A. because B. so C. but D. and

18. Laughing is good _______ your health.

A. for B. to C. with D. of

19. Choose the word that has the underlined part pronounced /3:/

A. dear B. pear C. earn D. heart

20. Choose one mistake and correct it.

I find carve eggshells boring because it takes a lot of time to complete one shell. A B C D

II. Put the verbs in the correct form.

1. I enjoy (fish) .................................................. because it (be) ……………….… relaxing.

2. Jane will play chess after she (finish) …………………………. school.

3. What …………………… your mother often (do) ………………………at weekends?

4. I think, in the future people (not play) ………………………………… individual games.

5. We find (arrange) ……… flowers interesting because it (help) …………… us relax.

6. I (not collect) ………….……………………… dolls when I grow up.

III. Complete the passage with the words given

bought competition singing there on English

Mary’s hobby is singing. She enjoys (1) ………………………… very much. When her brother (2) ………………………… a karaoke set last month, Mary was so glad that she sang every day after dinner. She likes to sing only (3) ………………………… songs. In fact, she has already sung all the songs found (4) ………………………… the karaoke discs. Minh is singing in the karaoke (5) ………………………… organized by the RC Center this Saturday. Her family is going (6) ………………………… to support her.

IV. Choose the best answer to complete the sentences by circling A, B, C or D

1. - ............... do you find making pottery? – I finding making pottery interesting.

A. What B. How C. Why D. Whe

2. Jenny...................two eggshells and he will continue the third one.

A. carves B. has carved C. carved D. will carved

3. My father hates ………… coffee. He prefers tea.

A. to drink B. drink C. drinks D. drinking

4. I have a temperature,………………………………. .

A. but I go to bed early B. so I feel tired

C. or I am putting on weight D. and I eat more vegetables

5. Which word has the underlined part pronounced differently from the others?

A. away B. answer C. sunburn D. picture

6. Which word has main stress differently from the others?

A. volunteer B. charity C. melody D. calorie

7. Beethoven ………….. a lot of songs.

A. composes B. composed C. has composed D. compose

8. Liz: I am so nervous thatI am putting on weight./ Tony: ……………………….. .

A. Wash your hand more B. Eat less junk food

C. Sleep more D. Sunbathe less

9. Jack spends almost his time staring at his smartphone, ……..….. is very short-sighted.

A. and B. or C. but D. so

10. My father loved …………. horse-riding when he was young.

A. doing B. going C. playing D. taking

11. She feels itchy and her nose is running. She says she has ………….. .

A. headache B. toothache C. allergy D. flu

12. Jenifer says that she ……………. collecting dolls, but she…………… in the future.

A. will like/ won’t continue C. likes/ continues

B. likes/ won’t continue D. will like/ continues

V. Choose the best answer to complete the passage:

Headache is a very common disease. The symptoms (1)…….. a headache are various. People may (2)……….. pains only one side of the head. Sometimes when the pain goes away, the head is sore. People have a headache (3) …………. they work too hard or they are too nervous about something. (4)……….. can help cure the disease but people usually have to do more than taking tablets. They can prevent headaches by changing their diets or their (5)…………… or simply by going to bed.

1. A. on B. in C. of D. at

2. A. be B. have C. happen D. take

3. A. when B. but C. so D. and

4. A. Medicine B. Doctor C. Sport D. Fruit

5. A. life B. lifestyles C. hobbies D. working

III. Complete each sentence so it means the same as the sentence above.

1. I didn’t go to school because I was sick.

-> I was sick, so ………………………………….

2. It will be good if you eat less meat and more vegetables.

-> You should ………………………………………………………………………

3. He likes playing computer games in his free time.

-> His hobby is ……………………………………………………………………..

4. I am interested in watching TV in the evening.-> I enjoy……………………………………

5. I think that learning English is important.->I find …………………………………………..

6. My brother enjoys coffee very much. -> Coffee ……………………………..………………..

7. What is the price of a plate of fried rice? -> How ……………………………………………..

8. This food has some meat and tofu. -> There …………………………………….……………...

9. Chicken is my sister’s favorite food. (likes) ->……………………………………………….....

10. There is sugar in many kinds of food. (have) -> ……………………………………………….

IV. Use the words given to write a paragraph about Huong’s hobby.

Huong/ be/ student/ class 7A/ Quang Trung school. Collect glass bottles/ be/ one of/ favorite hobbies. She/ start/ hobby/ when/ ten years old. She often/ share/ hobby/ sister. She/ find/ hobby/ interesting/ useful. She/ feel/ happy/ when/ look at/ beautiful flower vases/ make/ them. She/ continue/ hobby/ future/ because it/ help/ save/ environment.

V. Use the words given to write a paragraph about Kien’s hobby.

Kien/ be/ student/ class 7B/ Le Loi school. Play football/ be/ one of/ favorite hobbies. He/ start/ hobby/ when/ six years old. He often/ share/ hobby/ his friends. He/ find/ hobby/ interesting/ relaxing. He/ feel/ healthier/ when/ play football/ every day. He/ continue/ hobby/ future because it/ help/ keep fit.

Chúc bạn học tốt!

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Nông Lê Thanh Quang
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Tơ Van La Tơ
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Phương An
2 tháng 10 2016 lúc 21:27

\(PTK_{hc}=1,9375\times PTK_S=1,9375\times32=62\text{đ}vC\)

\(2\times NTK_X+1\times NTK_O=62\text{đ}vC\)

\(2\times NTK_X+16=62\)

\(2\times NTK_X=62-16\)

\(2\times NTK_X=46\)

\(NTK_X=\frac{46}{2}\)

\(NTK_X=23\text{đ}vC\)

=> Na

 

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AN TRAN DOAN
4 tháng 10 2016 lúc 18:52

PTKhợp chất=1,9375 * 32 =   62  (đvC)

PTKoxi = 16 (đvC) => PTK2x = 62 - 16 = 46 (đvC)

=> PTK= 46 : 2 = 23 (đvC) => NTK = 23 (đvC)

=> X là nguyên tố NATRI

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nguyen anh thuong
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Nguyễn Viết Hùng
6 tháng 12 2016 lúc 18:27

?_?

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long
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bui thi lan phuong
17 tháng 5 2017 lúc 9:55

mik nè

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long
17 tháng 5 2017 lúc 9:56

cho mình đi

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Sóc Lá Cây
17 tháng 5 2017 lúc 9:57

mình chỉ biết lên violet đề thi và kiểm tra

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Lookers Juvia
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Lookers Juvia
28 tháng 2 2017 lúc 19:04

pải làm đủ nka

ko đủ mk tét đấy

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