Professor Smith,along with his assistants, ____on the project day and night to meet the readline.
问题描述：
Professor Smith,along with his assistants, ____on the project day and night to meet the readline.
A.work B.working. C.is working D.are wonking
肯定不选D那选什么呢 解释一下
答
C
along with his assistants 是伴随状语,主语是Proffessor Smith,是单数