— I called you at six yesterday, but there was ______ answer.

— Did you? I ______ dinner at my friend's home.[ ]

A: not an; had

B: no; was having

C: not; was having

D: no; had

传导是指（）的物体各部分间的能量交换现象。

A.直接接触

B.间接接触

C.不接触

D.绝缘