We often see him help his classmate.改为被动语态
问题描述：
We often see him help his classmate.改为被动语态
答
he' s often seen to help his classmates by us.
答
His classmates are often seen helped by him.
答
He's often seen to help his classmate.
被动语态中不定式to要还原
答
为你解答。
We often see him help his classmate.改为被动语态
He is often seen to help his classmates by us.
他经常被我们看见去帮助同学。
解释：主动语态see sb do，被动语态 be seen to do。