保留灌肠时，臀部垫高约（）。

A.5cm

B.10cm

C.15cm

D.20cm

根据汉语提示，完成句子。

1. Keep trying! Don't                (错过) a good chance.

2. There are                (至少) 200 people going to the meeting.

3. The shark mainly                 (以……为食) fish and other sea animals.

4. I often                Mary                (错把……当作) Kate. Because they are twins.

5. —What do you think of "Harry Potter"?    —I think it is just                (一般).