Professor Sun, along with his assistants, __________ on the project day and night to meet the deadline.

A、work

B、working

C、is working

D、are working
出自:大学英语B2252

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