问题补充：
He the window of our classroom yesterday because he didn’t come to school．
A. mustn’t have broken
B. mightn’t have broken
C. shouldn’t have broken
D. couldn’t have broken
答案：
A. mustn’t have broken
B. mightn’t have broken
C. shouldn’t have broken
(答案→)D. couldn’t have broken
解析：考查推测。用情态动词can/ may/ must. 否定句用can/could .对过去推测用情态动词 +have done.
