一、关系代词选定要诀
定从要学好，删繁就简系首要，明确先行词，然后定关系词调；
指人主格用who，宾格whom好，事物用which，主/宾都可靠；
用that引定从，人/物均需要，非限制性定从句，切勿用that导；
关系词作宾语，常将其省略掉，若介词+关系词，关系词切勿抛，无论人/事物，who/that均不导，指人必whom，事物which邀；
as引定从，（部分）主句内容包，常含“正如”意，位置任意挑；
which如此用，用时思量好，有时含“消极”味，主句之后到；
such/ the same + as，固定搭配好，特殊用法务牢记，勿用乱了套；
whose作定语，人/物它全包，n. + of + whom/which，可与其对调。
二、只用that作关系代词的几种情况
先行（词）本身系数词，不定代词指事物，
人与事物共先行，There be中指物词作主语，
关系词定从中作表语，问句避免疑问词重复，
另有序数词/最高级，every/ the very/ the only，
以及不定代词若干个，名词前把事物来修饰，
以上情况请记清，只能使用that引导定从句。
[巩固练习]
请在横线上添上恰当的关系词。
1. We need comrades _____________ can help us.
2. The man _____________ you saw yesterday was a doctor from Beijing.
3. This is a story about a communist fighter _____________ name或the name of _____________ is Liu Hu-lan.
4. This is our classroom， _____________ windows或the windows of _____________ face the south.
5. Here is a book _____________ will give a lot of useful knowledge.
6. This is the song _____________ we like best.
7. I will never forget the day， on _____________ I first saw him.
8. This is the room _____________ Lao Liu once lived in.
9. Do you still remember the day on _____________ he joined the army？
10. The earth， _____________ we all know， moves around the sun.
11. _____________ is known to all， the earth is round.
12. The sun is bigger than the earth， _____________ is known to us all.
13. He did not study hard， _____________ led to his failure.
14. We used the same type of machine _____________ they did.
15. We have found such materials _____________ are used in their factory.
16. Here are five fish. The two _____________were caught yesterday are gold fish.
17. Everything _____________ I told you just now is true.
18. They talked of the things and persons _____________ they remembered in the school.
19. There are stars _____________ we still don‘t know in space.
20. Li Ying is not the girl _____________ she used to be ten years ago.
[试题答案]
1. who/that 2. who/whom/that/×
3. whose； whom 4. whose； which
5. which/ that 6. which/ ×
7. which 8. that/which/ ×
9. which 10. as
11. As 12. as/ which
13. which 14. as
15. as 16. that
17. that/ × 18. that/×
19. that/× 20. that
名师指点