Question

I found a number of people already working there。

I found a number of people already working there。I found a number of people already working there。这不是应该用过去完成时吗 为什么要用workingThe old man leaving his hometown several years ago found the place much changed. 为什么前面用leaving 后面用changed

Answer 1

1.I found a number of people already working there。I found a number of people already working there。这不是应该用过去完成时吗 为什么要用working
感官动词find后面的动词用ing形式，find sb doing sth的用法，说明found后面的work是正在进行。
2.The old man leaving his hometown several years ago found the place much changed. 为什么前面用leaving 后面用changed
前面leaving his hometown several years ago是现在分词短语做后置定语，相当于一个定语从句who left his hometown several years ago；后面是found sth done的用法，是英语常见的固定结构，其名称是《及物动词的复合结构》，其结构形式是： “及物动词+宾语（名词/代词）+宾语补足语（名词/代词；形容词、副词、介词短语、非谓语动词）”。经常用于此结构的常见及物动词： find,think,consider,feel,leave,keep,have,get,see,watch,notice,watch，observe等。

Answer 2

I found a number of people already working there。
我发现有许多人已经在那里工作了。

Answer 3

I found a number of people already working there。这不是应该用过去完成时吗

解析：这里working there是用现在分词作people的后置定语，代替了定语从句

The old man leaving his hometown several years ago found the place much changed. 为什么前面用leaving 后面用changed

解析：问题同上。
这里leaving his hometown several years ago用现在分词作old man定语，代替定从

现在分词做定语表示主动和进行.
There is a baby sleeping in the nursey
There is a baby who is sleeping in the nusrey.
当主句的主语和从句主语是同一个的时候并表示主动或进行时使用
过去分词表被动和完成,其它的同上.