Question

i found it was hard to learn english well when i

i found it was hard to learn english well when i was young
变为简单句

Answer 1

I found it hard to learn English well when young.
〔注释〕
1. 动词 find 可以跟复合宾语，把原句宾语从句中 was 删除，原复合句中的形式主语就成了简单句的形式宾语。
2. 把原时间状语从句的主语 I 和谓语动词 was 省略改为简化为 when young。