— I'm sorry I broke your coffee cup. 

— _____. [ ]

A. You're welcome

B. I don't know

C. You're right

D. It doesn't matter

白炽灯是靠钨丝白炽体的高温热辐射发光，它具有（）的特点。

A.泡壳尺寸小、强度高

B.结构简单

C.显色性好

D.使用方便