问题补充:
Professor Smith, along with his assistants, on the Project day and night to meet the deadline.
A. work
B. working
C. is working
D. are working
答案:
A. work
B. working
(答案→)C. is working
D. are working
解析:参考主谓一致。本句的主语是Professor Smith, along with his assistants,谓语动词要和前面的名词Professor Smith保持一致,故使用单数形式,排除AD项。B项不能单独做谓语。句意:史密斯教授和他的助手在夜以继日地做这项工作,以赶上最后期限。故C正确。