从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。
1. When did you finish your homework, at noon or in afternoon?
A. the; an B. /; the C. a; the D. the; /
2. If you want people to treat you nicely, you have to treat nicely, too.
A. their B. they C. them D. themselves
3. Yao Ming is 2.26 metres tall. It’s very to find a bed big enough for him.
A. easy B. important C. difficult D. interesting
4. — does your father wash his car?
—Once a week.
A. How much B. How often C. How many D. How long
