When____the work,you must be careful.A do B are doing C to do D d_英语解答

When____the work,you must be careful.
A do B are doing C to do D doing

人气：430 ℃　时间：2020-06-06 08:17:18

解答

你好,很高兴能够在这里回答你的问题,这道题的正确答案应该为：
D
when后没有主语,所以用doing
当做工作时,你一定要小心．