—What’s up? You look worried.—Well, I ______ on the problem for 5 hours but I ha

题干

—What’s up? You look worried.
—Well, I ______ on the problem for 5 hours but I haven’t got a single clue.

A．have worked	B．worked
C．will work	D．have been working

上一题下一题 0.85难度单项选择更新时间:2013-09-09 05:58:20

小学学科试题库

初中学科试题库

高中学科试题库