题目内容：

3.An expert, together with some assistants, ____ to help in this
work.
A. was sent B. were sent C. is sending D. are sending
翻译

优质解答

a.was sent.together with some assistants是插入语,主语还是an expert,所以选谓语是单数.由于专家是被“送”的,所以选a