题目

如图，直线a、b被直线c所截，若要a∥b，需增加条件    ▲   （填一个即可）. 答案：∠1=∠3、∠1=∠4或∠1+∠2=180°解析:根据两直线平行的判定定理，需增加的条件有∠1=∠3、∠1=∠4或∠1+∠2=180° John has got a fever these days, and he says he doesn’t want to see a doctor, but I’m afraid he has no _____________．        A．idea        B．treatment             C．alternative        D．chance