单项选择，从A、B、C中选出最佳的答案。
1）— Dad, must I finish my homework today?
— No, you______. You ______ do it tomorrow.
A. needn't/may
B. mustn't/can
C. won't/will
2）It's nearly seven o'clock. Jack ______ be back home at this moment.
A. must B. need C. can
3）Susan's parents have bought a large house with a swimming pool. It _____ be very expensive.
A. must B. can C. mustn’t
4）Here's my pen! I ______ it, and I finally ______ if.
A. am looking for/find
B. am looking for/look for
C. am finding/find