问题补充:
. When the teacher came in, the student pretended his lessons.
A. to do
B. to have done
C. to be doing
D. to be done
答案:
A. to do
B. to have done
(答案→)C. to be doing
D. to be done
解析:考查非谓语动词。句意:当老师进来时,这个学生假装正在做功课。不定式表示具体的将要进行的动作。结合语境可知不定式内容为正在进行的动作,故用进行时态的不定式,选C。