Question

-----Tom. You look very bored and tired.
-----Yes, I ______ my father on the farm until seven o’clock this morning.

A．have been helping

B．had helped

C．was helping

D．am helping

Answer 1

C

由表示过去的时间状语until seven o’clock this morning可知, 前面用过去进行时。本题注意不要受思维定势的影响而用现在完成进行时，要深入体会动作的时间性。