* Một bếp điện có ghi 220V- 1000W được sử dụng với hiệu điện thế 220V  để đun sôi 2,5l  nước từ nhiệt độ ban đầu là 20⁰C thì mất một thời gian là 15 phút. (Biết nhiệt dung riêng của nước là 4200J/kg.K)

a. Tính điện trở của bếp điện.

b. Tính hiệu suất của bếp

c. Dây đốt nóng của bếp được làm bằng nikenli tiết diện 0,02mm² điện trở suất  p = 0,4.10^-6Wm. Tính chiều dài của dây đốt nóng.             

d. Nếu mỗi ngày đun sôi 5l nước với các điều kiện như nêu trên thì trong 30 ngày sẽ phải trả bao nhiêu tiền điện cho việc đun nước dùng bếp điện này. Cho rằng giá mỗi kw.h là 1500đ.

* Rewrite each sentence beginning as shown, so that the meaning remains the same.
1. This winter is colder than the last winter.
The last winter ……………………………………………………………………………………………………………
2. Bill and Peter are too young to ride motor-cycles.
Bill and Peter are not ……………………………………………………………………………………………………
3. The last time Henry smoked a cigarette was in 2005.
Henry hasn’t ……………………………………………………………………………………………………………
4. The flood was so high that they had to live on the roofs.
It was such ………………………………………………………………………………………………………………
5. Jack is stopped by the police because he passes the speed limit.
If ……………………………………………………………………………………………………………………………
6. “If you had asked me, I would have lent you my car” he said to her.
He said (that) ……………………………………………………………………………………………………………
7. It’s cold in the morning, so the children go to school in heavy clothes.
Because of ………………………………………………………………………………………………………………
8. David has read a lot of books, however, he cannot find a good solution.
Although …………………………………………………………………………………………………………………
9. She asked, “How many Japanese students are there in your class, Tom?”
She asked Tom …………………………………………………………………………………………………………
10. People all over the country have helped the poor people in the flood region.
The poor people …………………………………………………………………………………………………………

* Fill each gap with a suitable word from the list given.

Projector had not been used in the classroom for study before 20 years ago. This (1) ………………………makes the lessons more interesting, (2) ………………………in natural science subjects including physics,
(3) ………………………, chemistry…, the scientific events are (4) ………………………through videos, pictures, and sounds. Students are usually (5) ………………………at how things happen on the screen, and they understand clearly about the lessons. This (6) ………………………screen helps children to (7)……………………more on the lessons and not feel boring as the traditional teaching (8)………………………. Before this device is used, teachers meet difficult explaining and (9)………………………the natural events to students. They must (10) ………………………pictures or draw on
the board by (11) ………………………, which took time but not (12) ………………………. In my (13)………………………, using projector is a great change, saves time in teaching and keeps children engaged.
It also (14) ………………………more information in an effective and detailed way. Besides, this change will be continued thanks to the development of (15) ………………………and Internet.

* Choose the best answer to complete the sentences.
1. We’re playing the old songs that I’m sure they will ……………………memories for you.
A. bring back B. preserve C. change D. imagine
2. Melinda has got into the ……………………of turning on the TV as soon as she gets home.
A. tradition B. habit C. behavior D. practice
3. Unless we do something now, hundreds of plant and animal species will …………………….
A. survive B. die out C. live on D. save
4. Her face was lively and bright as she ……………………the story from her childhood memories.
A. acted out B. kept C. used D. passed down
5. Every summer, they set off for their ……………………farmhouse which is 300 kilometers away from the city.
A. downtown B. metropolitan C. urban D. remote

* Write the correct form of the word in brackets.
1. Joe used to be an ………………………child, but now he has become more realistic. (imagine)
2. It is fundamental for everyone to maintain a ………………………active daily routine. (physical)
3. There didn’t use to be many forms of ………………………in my country in the past. (entertain)
4. This small village has its own ………………………dress, cuisine, folklore and handicrafts. (tradition)
5. In any circumstances, you shouldn’t let negative ………………………and bad habits ruin your life. (behave)
6. The villagers are better educated and more informed now – though ………………………is still widespread among the poor. (illiterate)

* Pick out the word whose underlined part is pronounced differently from that of the others.
1. A. lie B. height C. weigh D. pie
2. A. sugar B. snack C. strict D. seniority
3. A. helped B. liked C. watched D. posted
4. A. fatal B. adventure C. page D. generation
5. A. use B. unbelievable C. university D. uniform
6. A. good B. book C. bare-footed D. igloo

* Put the following words in the correct order.
1. I / I do / didn’t / now / like / use to / music /, but / western /.
………………………………………………………………………………………………………………………………
2. I / but I / now / used to / have short / have / a / one / long hair, /.
………………………………………………………………………………………………………………………………
3. As / used to / was / child, / walk / because / she / the town / so / a / small / everywhere /.
………………………………………………………………………………………………………………………………
4. He / used to / play / basketball player / sports, / never / but now / he’s / any / a / well-known /.
………………………………………………………………………………………………………………………………
5. This town / which is in / be in / high contrast to / extreme poverty / these days / used to / their wealth /.
………………………………………………………………………………………………………………………………

* Put the following words in the correct order.
1. I / I do / didn’t / now / like / use to / music /, but / western /.
………………………………………………………………………………………………………………………………
2. I / but I / now / used to / have short / have / a / one / long hair, /.
………………………………………………………………………………………………………………………………
3. As / used to / was / child, / walk / because / she / the town / so / a / small / everywhere /.
………………………………………………………………………………………………………………………………
4. He / used to / play / basketball player / sports, / never / but now / he’s / any / a / well-known /.
………………………………………………………………………………………………………………………………
5. This town / which is in / be in / high contrast to / extreme poverty / these days / used to / their wealth /.
………………………………………………………………………………………………………………………………