2016年职称英语卫生类语法：表示转折或对比关系的连词

1) but 但是。

He is rich but unhappy.

while 然而，表示对比意味。

Some people love cats,while others hate them.yet 然而 She said she would be late,yet she arrived on time.however 然而，可是，不过 She does not like him,however,I like him.

2) not……but……意思为"不是……而是……"

not和but 后面的用词要遵循一致原则。

They were not the bones of an animal,but (the bones) of a human being.