问题
选择题
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
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.