Question

—Where is Mother?—She is in the kitchen. S

—Where is Mother?—She is in the kitchen. She ________(do) the housework all morning.

Answer 1

has been doing

考查动词时态。句意表示母亲一上午都在做家务，现在仍在厨房做，故应用现在完成进行时表示从过去至今一直在持续的动作。