Nguyên tử cacbon có khối lượng = 1,9926 x10 mũ -23 g có nguyên tử khối: C = 12

a) Tính khối lượng của nguyên tử A biết nguyên tử khối của A là 1 đơn vị cacbon?
b) Tính nguyên tử khối của B biết 1 nguyên tử B nặng 2,98 x 10 mũ -23 g
c) Nguyên tử A nặng hay nhẹ hơn nguyên tử B bao nhiêu lần?

Một vật chuyển động không đều. Biết vận tốc TB trong 1/3 thời gian đầu bằng 12m/s, trong thời gian còn lại là 9m/s
a) Tính vận tốc TB trong thời gian chuyển động
b) Biết chiều dài của đoạn đường là 54km.Hãy tính thời gian đi hết cả đoạn đường

1. This bad boy hardly abided by school regulations last year, ……………….?
2. His sickness accounted for his failure last month, ………………?
3. Farmers account for 80% of Vietnamese population, ……………………..?
4. Add some sugar to your coffee, ………………….?
5. You had to agree with her proposal yesterday, ………………….?
6. You seldom agree with your friends about anything, …………………?
7. She won’t aim at being the best student this year, …………………?
8. My son ought to apply for that English contest, ………………………?
9. Your mother never arrives in another country, ………………………?
10. Let’s arrive at the camping site at 6:30 tomorrow, …………………….?
11.Come to your friend and ask for that book, ……………………?
12. He has rarely asked her out to dinner or movie since he knew her, ……………………?

13 We need to back up that chemist at his laboratory, ……………………?

14 That kid is about to be bred in a nursing home, ……………………?

15 He has hardly been in touch with her for a year, ……………………?

16 We shouldn’t be out of touch with these customers, ……………………?

17 China must be home to panda, ……………………?

18 He used to be into playing online games, ……………………?

19 They ought to bear in mind what you told them, ……………………?

20 This secret information will never be borne out, ……………………?

21 Those people are hardly benefiting from our project, ……………………?

22 Blow out the candles before going out, ……………………?

23 Let’s take the man who blew up our car to jail, ……………………?

24 In the past students had to bow to teachers, ……………………?

25 Brief me on what you did yesterday, ……………………?

Một người đi xe đạp dự định, đoạn đường đầu phải lên một cái dốc nên chỉ đi với vận tốc 6km/h trong thời gian 10 phút.Trên đoạn đường sau dài 5km với vận tốc 10km/h
a) Tính vận tốc TB của người đó trên cả quãng đường
b) Do phải lên dốc nên người đó đi đến đỉnh dốc (hết đoạn đường đầu) thì nghỉ mất 10' . Đoạn đường còn lại phải đi với vận tốc bao nhiu để đúng với thời gian dự định đi lúc đầu

1. Those workers …………… (bind) to a five year contract with a company at present.

2. We ………….(have) our gift ……….. (bring) to them before they ………. (leave) last night.

3. She …………. (deal) with that business man since she first ………. (met) him in 2001.

4. This village …………… (get) many problems if too much wine …………. (drink) everyday.

5. We ………….. (flee) from the city before the terrorists ……… (attack) it last Friday.

6. If the meat …………… (not) (freeze), we …………… (have) nothing to eat last night.

7. If they …………. (not) (let) (play) online games much, they ……… (study) harder now.

8. She ………. (have) her house ……….. (oversee) all the time since her car ………... (steal) last week.

9. If that proposal ………… (not) (withdraw) last year, we ………….. (withstand) air pollution here.

10. He …………. (swear) not to go to the game center again, but yesterday he ……… (ride) bicycle to it.

For example: 0. The fish ……………… (unfreeze) before the cooker …………. (come) tomorrow.
-> The fish will have been unfrozen before the cooker come tomorrow.

-> Những con cá sẽ được rả đông xong trước khi người đầu bếp đến ngày mai.

11. Yesterday we ……… (sting) by hundreds of bees when a heavy rain …………. (pour) down.

12. If they …………... (undergo) poverty, they ………….. (not) (spend) so much money last year.

13. Someone …………. (put) a box inside our house last night although the doors ……….. (shut) before.

14. When John ………… (meet) us yesterday, he …………. (mistake) for his brother who used to be our manager.

15. If a kid …………. (hurt) usually, his or her memory ………… (affect) negatively in the future.

16. Those fake books …………. (tear) before our office ………… (run) by Jane next Monday.

17. If a tiger ………… (not) (catch) in this area last month, lots of tourists ………… (come) here.

18. Yesterday a glass cover ………… (lay) on this table when a coconut fruit ………. (fall) on it.

19. Since 1980, many scientists ……….. (uphold) the idea that a livable planet should …….... (seek).

20. Our dog rarely …………. (sit) since he ……….. (have) his legs ………. (saw) after an accident last month.