选择方框中的动词词组，并用其适当形式填空。

小题1: _____________ your health because you are not strong .

小题2:We are _______________ seeing each other soon.

小题3:Don ’ t forget __________ the lights when you go out.

小题4:They should _________￥25 ________ the cartoon book.

小题5:We must ____________ to help those poor students.

2～4mol／L硫酸溶液（）。

A.包被液

B.稀释液

C.洗涤液

D.底物溶液

E.IA.中所用上述各种缓冲液的主要成分是