When he was opening the door he was that he was being followed by a policeman.A. conscio

问题补充：

When he was opening the door, he was that he was being followed by a policeman.

A. conscious

B. casual

C. careful

D. doubtful

答案：

(答案→)A. conscious

B. casual

C. careful

D. doubtful

解析：词义辨析. A.意识到的;自觉的 B.随便的;临时的 C.认真的 D. 可疑的.句意:当他打开门,他意识到他被一个警察跟着.选A.