The weather is really terrible these days. Tell the children to be________.

Don’t have a cold..

A．lucky

B．friendly

C．comfortable

D．careful

抗力形窝洞的制备要求如下，除外（）.

A.底平壁直的盒状洞形

B.点、线，角清晰锐利

C.窝洞应有一定的深度

D.应去除悬空的牙釉质

E.洞缘线应成圆缓曲线