1）be done可以是is done/was done/were done,這表示動(dòng)詞的一般現(xiàn)在式和一般過(guò)去式的被動(dòng)語(yǔ)態(tài),例如：The cup was broken by a child.由主動(dòng)句A boy broke a cup變來(lái)的.
have/has/had been done表示現(xiàn)在完成式和過(guò)去完成式的被動(dòng)語(yǔ)態(tài),例如：The film has been seen by all the students in our class.由主動(dòng)句All the student in our class have seen the film變來(lái)的.
2）while可以作為連詞表示轉(zhuǎn)折,但要清楚一點(diǎn),由while連接的兩個(gè)句子前后的語(yǔ)義形成的對(duì)比,而不是強(qiáng)烈的轉(zhuǎn)折.例如：
Ilike coffee while you prefer tea.
從上面的句子中可以發(fā)現(xiàn),while前后連接的兩個(gè)句子語(yǔ)義是相反的,前后形成對(duì)比.
而but前后兩句話是強(qiáng)烈的轉(zhuǎn)折.如：
ilike coffee,but i can't have it now since i am afraid i am not able to fall asleep.
從上面的句子可以發(fā)現(xiàn),but連接的兩個(gè)句子是強(qiáng)烈轉(zhuǎn)折的.