用适当的介词填空。

1. There are twelve months ____________ a year.

2. April is the fourth month ____________ the year.

3. My birthday is ____________ March 12th

4. We go to school ____________ Monday ____________ Friday.

5. Mother's Day is also ____________ May.

6. I eat lunch ____________ my family.

辽沈战役中实施“关门打狗”的战略，这个门指的是 [ ]

A、山海关

B、锦州

C、长春

D、沈阳