问题

Has your friend completed his design—Not yet. He _______ on it last night.
A:worked
B:has worked
C:is working
D:was working;
B:has worked
C:is working
D:was working;
正确答案是:
同类题型
When was first robot —In 1959.
Do you know what he was made by his father last night
.—________ have you been a reporter?—For more than three years
Open the window please, Mike. —____________?I didn’t hear what you said.
Michael put on a picture of YaoMing beside the bed to keep himself _____ of his own dreams.