1.The student is sitting next to me is sick now

1.The student is sitting next to me is sick now 1.The student who is sitting next to me is sick now.(who is sitting next to me 是定语从句)
或The student sitting next to me is sick now.(sitting next to me 是现在分词短语作定语)
2.I'm using the pen which be bought it yesterday
2.I'm using the pen which was bought yesterday.
(which was bought yesterday是定语从句,yesterday决定必须用过去时,which指代the pen,笔应该是被买的,另外后面的it是多余,the pen已经有which指代了,不需要it)
3.I'm going to work in the hospital where needs me
3.I'm going to work in the hospital which needs me.(which needs me是定语从句,which指代the hospital,是医院需要我,不是在医院需要我,所以,用which而不用where)
4.I'd like to buy that new model recorder but which is too expensive for me
4.I'd like to buy that new model recorder but it is too expensive for me.(有连词but,说明是个转折关系的并列句,不能用从句,因此要改which为it)
5.Henan is a province which population is the largest in China
5.Henan is a province whose population is the largest in China.(whose population is the largest in China是定语从句,修饰a province,其中whose指代the province's在从句中做定语,修饰population)
6.Is that factory which your father once worked in?
6.Is that factory the one (that) your father once worked in?(该句主句是Is that factory the one?,从句是(that) your father once worked in,如果用which,主句就缺少表语,就不完整了,所以要先补全主句,为避免重复,用the one代替前面的that factory,另外前面有先行词the one,后面从句的关系代词只能用that或省略,不能用which)
7.The woman who I spoke is from Canada.
7.The woman whom I spoke to is from Canada.(whom I spoke to 是定语从句,whom做spoke to的宾语,speak to sb.对某人讲话,是固定短语,在从句中充当表人的宾语严格意义上要用whom,只有口语中不严格的讲才可以用who)
8.He is one of the students who has been to the West Lake before.
8.He is one of the students who have been to the West Lake before.(定语从句who have been to the West Lake before修饰限定the students,因此要用复数形式.)