Many students at the school _______ on a project which relates to the unemployment problem.

选择一项:

A.
worked


B.
have worked


C.
have been working
出自:国家开放大学人文英语2

完成拼图验证

按住下方滑块,将拼图拖到缺口处后松开。

拼图背景,将小拼图拖到缺口处
向右拖动滑块