连词的定义及分类

连词用于连接单词、短语、从句或句子。根据性质和意义，连词可以分为并列连词和从属连词。并列连词连接两个互不依从的单词、短语或成分；从属连词主要引导状语从句和名词性从句。

并列连词的用法

表示的关系	并列连词
并列或递进	and both…and… neither…nor… not only…but(also)…
转折	but, yet, while
选择	or, or else, either … or …, not…but…
因果	for so

引导原因状语从句的连词
- because意为“因为”，语气最强，可用来回答why引导的疑问句，不能与so连用。
  - She didn’t follow the rule because she dislike it.
- since意为“由于；既然”，通常位于句首。
  - Since you have know it, I don’t have to tell you about it.
- as 意为“由于”，语气较弱。
  - As it is raining, please take an umbrella.
引导结果状语从句的连词
- so…that…意为“如此······以至于······”，so后加形容词或副词。
  - He is so nice that everyone likes him.
- such…that…意为“如此·······以至于······”，such后加名词或名词词组。
  - He is such a smart person that he can solve any problem.

引导目的状语从句的从属连词 so that/in order that 意为“为了······”。
- He runs quickly so that he won’t be late.
- He students hard in order that he can get high marks.
引导让步状语从句的从属连词though/although意为“虽然”。
- Although it was raining, he still went out.
- Even though he had the money, he wouldn’t buy it.
引导方式状语从句的从属连词
- as意为“按照······方式”。
  - She always does as her father tells her.
- as if/though意为“似乎；好像”。
  - He seemed unhappy as if someone bothered him.

引导时间状语从句的从属连词
- before意为“在······之前”，after意为“在······之后”。
  - After he came home, he turned on the light first.
- when与while意为“当······时”。when后可加延续性或非延续性动词；while后只能加延续性动词，常与进行时连用。
  - She went to school while her parents were sleeping.
引导条件状语从句的从属连词
- if意为“如果”；unless意为“除非”。
  - He will not succeed unless he works hard.
- as/so long as 意为“只要”。
  - As long as you like, you can take it home.

名词性从句可分为主语从句、宾语从句、表语从句和同位语从句，其从属连词主要有that，if，whether等。
I don’t know whether you like flowers.