问题补充：
根据句意，用所给动词的适当形式填空。
【小题1】We celebrate Christmas by sending (send) cards to each other.
【小题2】We should do as much as we can to help (help) them out of trouble.
【小题3】The whole class is divided (divide) into four groups.
【小题4】How much did you spend buying (buy) the new bike?
【小题5】The Green family were having, (have) supper at the table when I came into the house.
答案：
解析：
【小题1】介词后面通常用动词的ing形式做宾语；故答案为sending。
【小题2】句中as much as we can 做动词do的宾语，后面用动词不定式用作目的状语；故答案为to help。
【小题3】句子主语The whole class 和divide into构成了逻辑上的动宾关系，所以表达被动，即整个班级被分成了四组；故答案为is divided。
【小题4】spend time/money (in) doing sth意为“花费时间或金钱做某事”；故答案为buying。
【小题5】根据后面的when引导的时间状语从句可知句子的时态为过去时，并且表达“当我进来时格林一家正在吃饭”，用过去进行时；故答案为were having。
根据句意 用所给动词的适当形式填空。【小题1】We celebrate Christmas by sending (send) cards to each other.【小题2】W
