he worked hard _____it.He learned by himself.He worked hard ______英语解答

he worked hard _____it.
He learned by himself.He worked hard _____it.Now he is a great magician.
A.in
B.on
C.for
D.at
选什么为什么

人气：346 ℃　时间：2019-12-13 12:41:24

解答

D
work on ...是"着手做某事...", work at是"在...方面做"