—Do you know when your friend ___?

--I’m not sure. I will tell you when he _____?

A．does come; will come

B．comes; comes

C．will come; comes

D．will come, will come

请运用所学的化学知识解释下列现象：

①酒精灯打翻着火，用湿布盖灭．___________________________．

②装开水的保温瓶塞子有时候会跳出来，原因是_____________________．

③探究分子间间隔时用细玻璃管代替量筒做酒精和水混合的实验，通常是先加                  后加_______________，原因是___________________________．

④用武德合金替代纯铅做保险丝．_________________________．