8、关系词who与that指人时，也有不同情况分别用不同的关系词
（1）当主句是there be句型时，关系词用who。
（2）先行词是为anyone、those、someone、everyone、one等词时，关系词用who。
（3）当主句是who作疑问词时，关系词用that。
Who is that girl that is standing by the window?
（4）whom在从句中只作宾语，可被who取代。
9、whose作关系词既指人又指物，在从句中作定语。如：
Do you know Mr.Smith whose story is very moving ?
There is a room, whose window faces the river.
There is a room, the window of which faces the river.
10、关系代词as,在从句中作主语、宾语和表语。
（1）先行词被such和the same修饰，或句型as many（much）中，从句都用as 引导。
Such books as you bought are useful.
The school is just the same as it was 10 years age.
注意：区别
①such … that … 引导的结果状语从句。
They are such lovely children that we love them much.
②the same … that … 引导定语从句。
I want to use the same tool that you used just now.
（2）无先行词的定语从句用as和which引导。
区别：①意义上：as 含有“这点正如……一样”。②位置上：as 从句可置句首，也可在另处。
He didn’t pass the exam, as we had expected.
There is lots of air in loose snow, which can keep the cold out.
As is known, the earth is round, not flat.