问题补充：
The boy pretended when his parents entered the room.
A. reading
B. to reading
C. to be reading
D. having read
答案：
A. reading
B. to reading
(答案→)C. to be reading
D. having read
解析：考察pretend用法，pretend to be doing 是强调不定式的动作正在进行的过程中.
pretend to do是强调假装要做某事,而不一定正在进行或者是已经发生.
还有一种完成式pretend to have done 强调假装后面的动作已经完成.
根据题意当他的父母进入房间时，这个男孩假装正在读书，故选C。
