If you want to get good grades you should listen to the teacher in class.A. at first;

问题补充：

If you want to get good grades, , you should listen to the teacher in class.

A. at first; careful

B. first of all; carefully

C. for the first time; careful

D. first of; carefully

答案：

A. at first; careful

(答案→)B. first of all; carefully

C. for the first time; careful

D. first of; carefully

解析：此题考查副词或副词短语，first of all表示首先，carefully表示仔细地，用来 修饰listen to。