Unless:conj.除非,如果不
unless是从属连词,引导条件状语从句,含有否定意义,相当于if条件状语从句的否定形式.所以unless = if not.注意：unless引导的条件状语从句和if条件状语从句,与其它时间状语从句一样,用一般现在时代替将来时.
1.Unless you take more care,you’ll have an accident.
(如果不多加小心的话,你会出事故的.)
2.My baby sister never cries unless she is hungry.
(我那刚出生的妹妹除非饿了,否则她是从来不哭的.)
3.Unless bad weather stops me,I jog every day.
(除非坏天气阻拦我,否则每天我都慢跑的.)
1.although较正式,语气强
Although he was tired,he went on working.
2.although引导的从句放在主句前后均可,有时还可放在句中.
Although many difficulties are still ahead,we are determined to make greater achievements.尽管在前面的道路上还有许多困难,但是,我们决心要取得更大的成就.
He often helps me with my English although he is quite busy.尽管他相当忙,但是还常常帮我学英语.
3.although引导的从句不能与but,however连用,但可与yet,still连用.不能说：Although he was old,but he worked hard.应把but去掉.当然,保留but而去Although也可.
注意:although 的几不:
although不能指假设的情况
although不能作并列连词
although不能作副词,放在词尾