牛津實用英語語法:306 被動態動詞后的不定式結構
A 不定式結構用在acknowledge，assume，believe，claim，consider，estimate，feel，find，know，presume，report，say，think，under- stand等動詞之后。
People consider/know/think等that he is這類句子有兩種被動形式：
It is considered/known/thought etc.that he is
He is considered/known/thought etc.to be
同樣：
People said that he was jealous of her.
人們說他妒忌她。相當于：
It was said that he was
He was said to be jealous of her.
據說他妒忌她。
在這兩種結構中，用不定式的后一結構比較簡潔。它主要用于be，盡管有時其他動詞的不定式也可以這樣用：
He is thought to have information which will be useful to the police.
人們認為他掌握了對警察有用的情況。
如句中所想到的內容涉及到以前的動作，則使用不定式的完成式，因此：
People believed that he was相當于：
It was believed that he was/He was believed to have been
People know that he was相當于：
It is known that he was/He is known to have been
這種結構可與任何動詞的不定式的完成式連用。
B 不定式結構用在suppose后
1 suppose的被動態之后可以接任何動詞的不定式的一般式，但這種結構通常都含有這是一種責任、義務的意思，因此并不是同suppose的主動態(常意為推測)完全對應的形式：
You are supposed to know how to drive.
你本該會開車。相當于：
It is your duty to know/You should know how to drive.
會開車是你的責任。/你該知道怎么開車。
但He is supposed to be in Paris既可能意思是他應該在那里，也可能是指人們猜想他在那里。
2 suppose的被動態后面同樣可以跟任何動詞的不定式的完成式。這種結構可以有責任和義務的含義，但也常常沒有這種含義：
You are supposed to have finished.相當于：
You should have finished.
你早就應該完成了。
但是：
He is supposed to have escaped disguised as a woman.相當于：
People suppose that he escaped
據猜測他是喬裝打扮成女人逃跑的。
C 用在被動態動詞后面的不定式通常是帶to的不定式，盡管主動態動詞后面可能帶的是不帶to的不定式：
主動態： We saw them go out.
我們看見他們出去了。
被動態： They were seen to go out.
有人看見他們出去了。
主動態： He made us work.
他強迫我們干活。
被動態： We were made to work.
我們被迫干活。
然而，惟獨let的被動態后面的不定式不帶to：
主動態： They let us go.
他們讓我們走了。
被動態： We were let go.
我們被允許走開。
D 不定式的進行式可用于如下動詞的被動式之后：believe， know，report，say，suppose，think，understand等。
He is believed/known/said/supposed/thought to be living abroad.相當于：
People believe/know/say/suppose/think that he is living abroad.
據信/據知/據說/據猜測/據認為他住在國外。
You are supposed to be working.相當于：
You should be working.
你本應在工作。
在這里也可用不定式的完成進行式：
He is believed to have been waiting for a message.相當于：
People believed that he was waiting for a message.
據信他當時一直在等待消息。
You are supposed to have been working.相當于：
You should have been working.
你那時本該一直在工作。
A 不定式結構用在acknowledge，assume，believe，claim，consider，estimate，feel，find，know，presume，report，say，think，under- stand等動詞之后。
People consider/know/think等that he is這類句子有兩種被動形式：
It is considered/known/thought etc.that he is
He is considered/known/thought etc.to be
同樣：
People said that he was jealous of her.
人們說他妒忌她。相當于：
It was said that he was
He was said to be jealous of her.
據說他妒忌她。
在這兩種結構中，用不定式的后一結構比較簡潔。它主要用于be，盡管有時其他動詞的不定式也可以這樣用：
He is thought to have information which will be useful to the police.
人們認為他掌握了對警察有用的情況。
如句中所想到的內容涉及到以前的動作，則使用不定式的完成式，因此：
People believed that he was相當于：
It was believed that he was/He was believed to have been
People know that he was相當于：
It is known that he was/He is known to have been
這種結構可與任何動詞的不定式的完成式連用。
B 不定式結構用在suppose后
1 suppose的被動態之后可以接任何動詞的不定式的一般式，但這種結構通常都含有這是一種責任、義務的意思，因此并不是同suppose的主動態(常意為推測)完全對應的形式：
You are supposed to know how to drive.
你本該會開車。相當于：
It is your duty to know/You should know how to drive.
會開車是你的責任。/你該知道怎么開車。
但He is supposed to be in Paris既可能意思是他應該在那里，也可能是指人們猜想他在那里。
2 suppose的被動態后面同樣可以跟任何動詞的不定式的完成式。這種結構可以有責任和義務的含義，但也常常沒有這種含義：
You are supposed to have finished.相當于：
You should have finished.
你早就應該完成了。
但是：
He is supposed to have escaped disguised as a woman.相當于：
People suppose that he escaped
據猜測他是喬裝打扮成女人逃跑的。
C 用在被動態動詞后面的不定式通常是帶to的不定式，盡管主動態動詞后面可能帶的是不帶to的不定式：
主動態： We saw them go out.
我們看見他們出去了。
被動態： They were seen to go out.
有人看見他們出去了。
主動態： He made us work.
他強迫我們干活。
被動態： We were made to work.
我們被迫干活。
然而，惟獨let的被動態后面的不定式不帶to：
主動態： They let us go.
他們讓我們走了。
被動態： We were let go.
我們被允許走開。
D 不定式的進行式可用于如下動詞的被動式之后：believe， know，report，say，suppose，think，understand等。
He is believed/known/said/supposed/thought to be living abroad.相當于：
People believe/know/say/suppose/think that he is living abroad.
據信/據知/據說/據猜測/據認為他住在國外。
You are supposed to be working.相當于：
You should be working.
你本應在工作。
在這里也可用不定式的完成進行式：
He is believed to have been waiting for a message.相當于：
People believed that he was waiting for a message.
據信他當時一直在等待消息。
You are supposed to have been working.相當于：
You should have been working.
你那時本該一直在工作。
