题目内容
1.Before ________ , we must check the machines.A. using them B. having used C. use them D. being used
答案:A
提示:
提示:
| 题目考察非谓语动词——动名词的意义用法
|
练习册系列答案
相关题目
题目内容
1.Before ________ , we must check the machines.A. using them B. having used C. use them D. being used
| 题目考察非谓语动词——动名词的意义用法
|