根据句意，用所给动词的适当形式填空。

小题1:We celebrate Christmas by _______ (send) cards to each other.

小题2:We should do as much as we can __________ (help) them out of trouble.

小题3:The whole class ___________ (divide) into four groups.

小题4:How much did you spend _________ (buy) the new bike?

小题5:The Green family __________ (have) supper at the table when I came into the house.

下列叙述正确的是（　　）

A．

此装置可防止铁钉生锈

B．

此装置可除去CO₂中混有的SO₂

C．

此装置可验证HCl气体在水中的溶解性

D．

此装置可用于实验室制取乙酸乙酯