Professor Li,along with his assistant,_____ on the project day an_英语解答

Professor Li,along with his assistant,_____ on the project day and night to meet the deadline.
A work B working C is working D was working
这题选什么?
为什么是这样

人气：230 ℃　时间：2020-09-22 07:13:04

解答

C is working 正在日以继夜的工作,along with his assistant,是插入语,不应被视为主语一部分,主语只是李教授,是单数,A是一般状态,且是复数,D是过去正在进行