Listen carefully you can’t hear what the teacher is saying.A. andB. thenC. or D. but

问题补充：

Listen carefully, you can’t hear what the teacher is saying.

A. and

B. then

C. or

D. but

答案：

A. and

B. then

(答案→)C. or

D. but

解析：根据前句子的关系，可知答案C符合题意，意思为转折关系，表示否则，故选C