Hearing their grandpa was coming, they began to ________ the work to prepare for a nice dinner.

A．set off　　　　　

B．set down

C．set aside　　　

D．set about

下面不属于三级过滤的是（）。

A.领油大桶到固定储油箱

B.储油箱到油壶

C.油壶到润滑部位

D.油桶到润滑部位