When youwant to work for our country in the future, ________, we should have strongbody and rich kno

When youwant to work for our country in the future, ________, we should have strongbody and rich knowledge.

A.at first

B.first of all

C.for the first time

D.after all

答案及解析： B

解析：

First of all 首先，第一的意思