连词分为并列连词和从属连词两大类。 并列连词是连接主语与主语，谓语与 谓语，句子与句子，分词与分词的词， 它要求前后两部分有相同的形式和语 法作用；而从属连词一般连接主句与 从句，从句形式有名词性从句，定语 从句和状语从句等。
并列连词： 并列连词可用来连接词与词，词组 与词组，分句与分句。常用的并列连词有： and，as well as，both … and，not only … but also，not … but，neither … nor，either … or，or，but ，yet，for（因 为），so（所以），while（而），when （这时）等。
? Both my brother and my sister are teachers. ? His room is bright but mine is gloomy（暗沉沉的）. ? He can not only repair radios but also fix them. ? It is a glorious（光荣的）yet difficult task. ? Strike while iron is hot.
从属连词 ? 一．引导时间状语从句的从属连词有： 1. when There was prolonged applause when he began to speak. 2. While We should strike while the iron is hot. 3. As As (When) he entered, the hall burst into thunderous applause. 4. After After I visit Shanghai I'll travel up the Yangtze.
5. Before It would be months before he was fit for the work. 6. Since It is just a week since we arrived here. 7. Until (till) I shall stay here until (till) I've completed my studies. 8. as soon as As soon as he got well, he went back to work. 9. Once Once he said that, I knew he was lying.
? 二．引导原因状语从句的从属连词有： 1. because He failed because he was too careless. 2. As As it was already rather dark, we decided to stop at the temple for the night. 3. Since Since you don't want to go, we won't force you to.
? 4. now that Now that you are all back, we'd better start the work right away. 5. Considering (that) They did the job quite well considering (that) they had no experience. 6. Seeing that Seeing that (Since) nobody was very enthusiastic about it, they decided to cancel the trip.
? 三．引导条件状语从句的从属连词有： 1. if If you can do it, so can I. 2. Even if We wouldn't lose heart even if we should fail ten times. 3. Unless I won't go unless you want me to. 4. In case We'd better take our raincoats in case it should rain (rains).
? 5. Provided /providing (that) I'll come provided (providing) (that) you let me know in good time. ? 6. Suppose/supposing (that) ? Suppose (Supposing) (that) he won't agree, what shall we do? ? 7. As (so) long as ? You may use the room as long as you keep it clean. ? 8. On condition (that) I'll lend you the book on condition (that) you return it on Monday.
四． 引导让步状语从句的从属连词有： 1. although / though Everybody worked with great enthusiasm although/though the weather was extremely cold. 2. even if (though) Even if I have to walk all the way I'll get there.
? 3. whatever，whenever，whoever， whichever, wherever…