与气体放电光源相比，热辐射光源的特点是（）。

A.结构简单、使用方便

B.光效较高

C.显色性较差

D.使用寿命长

—Is there ______ wrong with your watch?

—Yes. It doesn't work well. That's why I was late today.[ ]

A. something

B. nothing

C. anything

D. everything