=>
2/
1. G
2. A
3. F
4. C
5. D
6. E
3/
1. have studied
2. is ringing
3. Have/finished
4. called
5. were/doing
6. walking
7. misunderstand
8. attentively
4/
1. excited -> exciting
2. was -> were
5/
1. don't practise
2. should be used
3. should complain
4. to switch