Someone saw him swam in the lake yesterday.改为被动语态He__ __ __swim in the lake yesterday.
问题描述：
Someone saw him swam in the lake yesterday.改为被动语态He__ __ __swim in the lake yesterday.
答
had been see
答
was seen to
答
was seen to 遵循的规律是“主动不加to ,被动补上去”