状语从句的省略必须满足这2个条件吗？

Question

看到有人说：
状语从句同时具备下列两个条件:①主句和从句的主语一致，或从句主语为it；②从句主要动词是be的某种形式。从句中的主语和be动词常可省略。
那么，我想问的是：如果满足条件①，而不满足②的情况下，是否就可以省略从句主语（若从句主语是it，则it 也可省略吗）
看了1楼的回答，能否多举几个例子啊？

Answer 1

只需满足条件①，而不必满足条件②，状语从句就可省略主语而改为分词形式。如：After he had finished his assightment，he went homes。此句可变为：After having finished his assightment，he went home。

Being very tired,they stopped to rest.