It's on the festival occasions________ the family get together________ he misses his late father.

A．where; that

B．which; when

C．when; that

D．that; when

胶带输送机某一部分突然跑偏的原因是（）。

A.胶带拉力过紧，承载能力过大

B.胶带有部分弯曲，接头中心未对齐

C.胶带成槽性不好