1.His head soon appeared out of the second storey window,from where he could see nothing but trees.强调来源时,where 前可用介词.
2.I often called on the friend in whose factory there are many workers and building.in whose factory 在定语从句中作状语.
3.I have a brother,who works as a doctor.用 he的话,两个分句没有
逻辑联系了.
4.My family that/who are all football fans will go to watch the world cup 关系代词在定语从句中作主语时,that/who 都可以.
5.Don't read such books as will defile your mind 先行词前有such/so/the same时,用关系代词as引导定语从句.