问题补充：
Not having work out the problem,leave the office．
A. so he was not allowed to
B. and he didn’t want to
C. the teacher couldn’t make him
D. he couldn’t free himself to
答案：
A. so he was not allowed to
B. and he didn’t want to
C. the teacher couldn’t make him
(答案→)D. he couldn’t free himself to
解析：状语用的是Not having work out由此可知主句的主语是要执行此非谓语动作。句意： 没有解决这个问题他不想离开办公室。
