问题补充：
The airport next year will help promote tourism in this area.
A. being completed
B. to be completed
C. completed
D. having been completed
答案：
A. being completed
(答案→)B. to be completed
C. completed
D. having been completed
解析：句意：明年即将完工的机场将促进这个地区旅游业的发展。To be completed作后置定语修饰the airport，另外complete与其逻辑主语（the airport）是动宾关系，故用被动；另外句中有next year，表示还没有完工，综合起来，故选B。being completed表示正在被完成；completed表示完成了，含有被动和完成；having been completed表示已经完成了，表示该动作先于谓语动词动作发生。
【考点定位】考察非谓语动词用法。
