Tom is tall while his brother is short. 汤姆个儿很高,而他的兄弟却很矮。
It's raining hard，however，we must go out. 雨下得很大，然而我们必须出去。
I’d like to go with you, however my hands are full. 我想和你一块儿去,可是我忙不过来。
特别提醒: though, although(虽然、尽管)不能与but(但是)连用。
虽然他很累,但是他没有停止工作。
误:Although he is very tired, but he doesn’t stop working.
正:Although he is very tired, he doesn’t stop working.
正:He is very tired, but he doesn’t stop working.
3．表示选择关系的并列句
并列连词:or(或者;否则,要不然),either...or...(或者……或者……),neither... nor...(既不……又不……)等。
or有两重含义：
(1)译为“或者”，表示选择。
Now you can have a rest or you can go to the cinema．现在你可以休息，或者去看电影。
Do you like English or math?
(2)译为“否则”、“要不然”，表示条件。
You must tell the truth，or you will be punished．你必须说真话，否则你将会受到惩罚。
You must tell the truth, or you will be punished. 你必须说真话,否则你将会受到惩罚。
Either you can do it by yourself, or you can ask someone else to do it. 你或者自己做,或者让别人去做
Either you or I am going there tomorrow. 明天要么你去那里，要么我去那里。
特别提醒: (1)“祈使句+or+简单句”。祈使句表示一个条件，并列连词or后的简单句则表示一个不愉快或不理想的结果。
Call a taxi, or you’ll miss the train.
(If you don’t call a taxi, you’ll miss the train. )