Do we ____ (must,have to) be quiet in the shool library?

问题描述:

Do we ____ (must,have to) be quiet in the shool library?

Do we have to be quiet in the shool library?=Must we be quiet in the shool library?Who do we have to thank for this fiasco? 我们遭此惨败怨谁呢?Do we have to wear evening dress for the banquet?我们是不...