except
1.except用作连接词作unless解现在很不普通。
2.except用作介词后面不但可以接名词或代词，也可以接介词、副词或以that、when等词引导的从句。例如：
- He has always been in good health except in the past few days.
- He has always been in good health except quite recently.
- He has always been in good health except that he has had a slight headache in the past few days.
- He has always been in good health except when he had a slight headache.
3.except for作“除了…外”解。例如：The essay is well written except for a few mistakes in the last paragraph. 这句里的for不可省去，下面各句里的for也不可省去：
- The boy was unhurt except for a few scratches.
- The room was deserted except for a little girl.
- The wall was bare except for some posters.
- He went abroad and did not return to his country except for a short visit.
4.There is a pen on the table except a pencil里用except是错的，该改作besides。There is nothing on the table except a pencil里的except用得不错，但也可以改作besides。There is no pen on the table except a pencil里用except是错的，该把全句改作There is a pencil on the table, but there is no pen。
