—Jane, have you finished your paper?
—No, I my sister with her drawing all the morning.
A. help
B. helped
C. was helping
D. have been helping
网友回答
A. help
B. helped
C. was helping
(答案→)D. have been helping
解析：考查时态。本题的关键词是后面的时间状语all the morning该词与现在完成进行时连用，表示动作从过去开始一直持续到现在，还在发生。句意：—Jane,你写完论文了吗？—没有，整个早晨我都在帮助我的姐姐在画画。故D正确。