英文改错题.求详解

问题描述:

英文改错题.求详解
When it (1)grows dark ,she turned a suitcase into a bed and put the children inside it,(2)covered them with all the clothes she could find.
为什麽第一个不改成had grown而改成grew?
第二个为什麽改成covering?

1.过去完成时你可以想成是过去的过去,但是“天色渐黑”与“她把箱子变成床把孩子放进去”是同时的发生的事.所以都用一般现在时就好.
2.主语是she,第二个句子要表达的是she covered them...,是主动语态,所以要用动词的主动态形式,也就是动词ing