:red_cross:Arriving home, the door was found locked. (主从的主语不一致）
:check: Arriving home, I found the door was locked. (改）
:red_cross: Looking out of the window, there are lots of people in the street.(主从的主语不一致,there be 结构不能用分词从句）
:check: Looking out of the window, I saw lots of people in the street.
When I entered the room, I found nobody in it. = Entering the room, I found nobody in it.
When the city is seen from the hill, it looks like a garden. (主句：it 从句：the city 一致， 从句是被动语态）
= Seen from the hill, the city looks like a grarden.