主句：

He finished his homework on time.

从句：Knowing that his parents were waiting.

解析：相当于"Although his parents were waiting"，表示尽管知道父母在等，他还是按时完成了作业。

主句：

She passed the exam.

从句：Despite the heavy rain.

解析：相当于"Although it was raining heavily"，表示尽管下着大雨，她还是通过了考试。

主句：

They started the project.

从句：Feeling overwhelmed.

解析：相当于"Although they felt overwhelmed"，表示尽管感到不知所措，他们还是启动了项目。

主句：

He continued to run.

从句：Knowing the finish line was in sight.

解析：相当于"Although the finish line was in sight"，表示尽管终点就在眼前，他还是坚持跑完了。

主句：

We reached the summit.

从句：Despite the strong winds.

解析：相当于"Although the winds were strong"，表示尽管风很大，他们还是登上了山顶。

补充说明：

动词ing作让步状语时，通常置于句首或句中，但需用"Despite"、"Knowing"、"Though"等引导。- 若需强调"尽管"，也可用"Although"，但需将从句置于句首。以上例句均符合英语语法规则，通过动词ing形式简洁地表达了让步关系。