问题补充：
his project, the boy had to stay up late.
A. Not finishing
B. Not finished
C. Having not finished
D. Not having finished
答案：
A. Not finishing
B. Not finished
C. Having not finished
(答案→)D. Not having finished
解析：句意：这个男孩没有完成他的项目，不得不熬夜了。句中考察非谓语动词，finish 这个动词的逻辑主语是the boy是主动关系，not finish没有完成这个动作发生在主句谓语动词had to 之前，故用完成时的形式。值得注意的是否定形式的完成时要用Not having finished的形式，而没有Having not finished的形式，但是有Having never finished的形式。故选D.
