单项选择题

We ______ on it for many hours but we have not yet reached any conclusion.

A．work
B．have been worked
C．have been working
D．are working
<上一题 目录 下一题>
热门 试题

单项选择题
My boss asked me to answer the phone, to take all messages, and ______ some letters.
A．to type
B．typing
C．type
D．typewrite
单项选择题
It's high time you ______ to work on the plan for our journey to those beautiful mountains in Northern Europe.
A．start
B．would start
C．started
D．had started
相关试题