— According to my grandma, it is a good idea to eat chicken soup when you have a cold.

— _____, scientists agree with her.[ ]

A. Sooner or later

B. Once in a while

C. To be exact

D. Believe it or not

换风口时，卸下吹管后，往往要堵几砣炮泥，它的作用（）。

A.不让火往外冒，伤人

B.防止风口塌焦炭

C.防煤气中毒

C.防渣铁流出