I was in charge of grading all the assigned homework.I never had trouble [doing] it,为什么是doing it?

分类: 作业答案 • 2022-05-17 08:52:07

问题描述：

I was in charge of grading all the assigned homework.I never had trouble [doing] it,
为什么是doing it?

答

because they arevv nut

答

Have trouble （in） doing sth。

答

have trouble (in) doing sth.
这里省略的介词 in,介词后面都用ing的.