1. may

2. had to

3. couldn't

4. may I

5. used to

6. May you

7. used to

8. mustn't/ can't

9. can

10. ought to

11. might

12. may

13. didn't have to

14. needn't

15. can't take

1, i'm sorry to bother you while you're working but i................ask you a question(can/had to/must/may)

2,we..............ensure the telegram arrives in time (had to/mustn't /'d rather/might)

3,he.................keep his family because his wages were too low(couldn't/mustn't /can't/didn't have to)

4,...........make an appointment to see the doctor?(may i/could i/will i/shall i)

5,i ...................go swimming then i young(could/would/used to/both b&c)

6,................take this letter to the post office,please?(may you/must you/would you/X)

7,in our family mu father........................sit at the top of the table(used to/had to/ought to/must)

8,i................swim in this water:it is much too cold(mightn't/mustn't/can't/don't have to)

9,you..........imagine my surprise when i heard the news(can/ought to/will/all of these)

10,you................do some work instead of sitting there reading the paper(would rather/ought to/won't/don't have to)

11,be careful how you hold that jug it.............break easily(may/ought to/will/might)

12,i am not sure where to go for my holiday,but i......................go to china(should/may/have to/needn't)

13,we hag free tickets,so we.................pay to get into the concert(didn't have to/couldn't/mustn't/shouldn't)

14,shall i clean the window today?no you.....................(mustn't/needn't/on't have/shouldn't

15,you have been traveling all day.you......................a walk now(could take/can't take/can take/my take

=>

1. may

2. had to

3. couldn't

4. may I

5. used to

6. May you

7. used to

8. mustn't/ can't

9. can

10. ought to

11. might

12. may

13. didn't have to

14. needn't

15. can't take