1. You … be very attentive and careful if you carry out this experiment. a) should; b) can; c) may; d) had to. 2. The electron spectrometer used for the research … to be of a new type. a) must; b) is; c) are; d) may. 3. Theoretically any element … be able to force any element below it in the series. a) can; b) might; c) should; d) is; e) may. 4. Liquid air … be evaporated. a) may; b) must; c) can. 5. A substance … be crystalline and show no external regularity. a) had to; b) may; c) should. 6. No animal … live without oxygen. a) can; b) may; c) should; d) had to. 7. You … remember the properties of matter. a) may; b) must; c) have to.

1.She was invited to the party, wasn't she?
2. Your daughter went to this school, didn't she?
3. You didn't forget to call your mother, did you?
4. Mr.Grant sent us an e-mail, didn't he?
5. You didn't pass the interview, did you?
6. They lost the match, didn't they?
7. He didn't do it, did he?
8. They weren't happy, were they?
9. She had to do it, didn't she?
10. She didn't tell you about it, did she?
11. Your boss didn't like your project, did he?
12. The lecture began half an hour ago, didn't it?
13. They weren't friends, were they?
14. He was a good teacher, wasn't he?
15. That wasn't your fault, was it?
16. He used to smoke a lot, didn't he?
17. It used to be a club,. didn't it?

Jessica has already
1)packed her suitcase
2) made her bed
3) switched off lights
4) watered plants
5) had a shower
6) taken the cat to the neighbour

Robert has already 
1) packed suitcase
2)canceled visits
3)turned off computer
4)closed windows
5)tidy the room(но ето не точно)
6)washed hair

Jessica has not
1)packed suitcase yet
2)made bed yet
3)switched off lights yet
4)watered plants yet
5)hade a shower yet
6)taken the cat to the neighbour yet

Robert has not
1)packed suitcase yet
2) canceled visits yet
3) turned off computer yet
4) closed windows yet
5)tidy the room yet(тоже неточно)
6)washed hair yet