【单选题】
20. Only when he had handed in his exam paper ____ he had made several mistakes.
【单选题】
People’s hearts ____ the children whose parents died in the accident.
【单选题】
A sudden idea ____ to him that he might try the new method.
【单选题】
We often get ____ when people cut in line.
【单选题】
“Can I help you?” “Well, I’m afraid the box is too heavy for you, ____ thank you all the same.”
【单选题】
A guest arrived ____ I was doing my housework.
【单选题】
—OK, $ 500, but that is my last offer. —____.?
【判断题】
空间曲线必穿过法平面和从切平面,但不穿过切平面.