— I went to your house yesterday afternoon, but you were not in.

— Sorry. I _______ basketball with my classmates.

A．am playing

B．was playing

C．played

D．have played

在测定柴油的闪点时，常测出的是（）。

A．闪点的上限

B．闪点的下限

C．自燃点

D．燃点