1.be done和have/has/had been done之间区别!请举例!2.表转折时while与but用法区别最好举例

1）be done可以是is done/was done/were done,这表示动词的一般现在式和一般过去式的被动语态,例如：The cup was broken by a child.由主动句A boy broke a cup变来的.
have/has/had been done表示现在完成式和过去完成式的被动语态,例如：The film has been seen by all the students in our class.由主动句All the student in our class have seen the film变来的.
2）while可以作为连词表示转折,但要清楚一点,由while连接的两个句子前后的语义形成的对比,而不是强烈的转折.例如：
Ilike coffee while you prefer tea.
从上面的句子中可以发现,while前后连接的两个句子语义是相反的,前后形成对比.
而but前后两句话是强烈的转折.如：
ilike coffee,but i can't have it now since i am afraid i am not able to fall asleep.
从上面的句子可以发现,but连接的两个句子是强烈转折的.