Heard too many people complain about

你这个句子不完整么~~
应该就用hearing
On hearing too many people complaining about sth., I did sth..
或者是Having heard too many people complain about....
不会直接就用heard开头的。

原句是不正确的 应该就用hearing
动名词在句中作主语放在句首，hearing是非谓语动词
所以是Hearing too many people complain about,…….
要用heard话在之前也要加上动名词形式的have，即having
但和直接用hearing的状态有所不同，时间关系上有区别
前者是现在状态，后者是已完成的状态
Having heard too many people complain about,…….

After hearing too many people comlain about money, I...

Heard too many people complain about这个句子是完整的，楼上的意见都不准确。为什么是完整的呢？这句话在口语中是非常常用的。句子是完整的，省略了众所周知的主语而已。这种用法在口语中非常普遍。例如“Yes？”“Got it?”“Understand?”难道这些句子不完整？是不是？呵呵

最后举个例子“heard a lot about you”，中文是“久闻大名/如雷贯耳”