the project in time the staff were working at weekends.A. CompetingB. Having completedC.

问题补充：

the project in time, the staff were working at weekends.

A. Competing

B. Having completed

C. To have completed

D. To complete

答案：

A. Competing

B. Having completed

C. To have completed

D. To complete

解析：

to complete the project in time为动词不定式作目的状语。A表示正在进行；B表示该动作发生在主句谓语之前；C常用在某些固定句式中。