Lucy,could I use your computer?Sorry,I'm going to _____ now.

问题描述:

Lucy,could I use your computer?Sorry,I'm going to _____ now.
A:work at it B:work it at C:work it on D:work on it(告诉语法啊)

D:work on it
怎么解释呢,work on从事
没有work at这个短语啊