怎甚是被動句(英文)????

In grammar, the voice of a verb describes the relationship between the action (or state) that the verb expresses and the participants identified by its arguments (subject, object, etc.). When the subject is the agent or actor of the verb, the verb is in the active voice (主動語態). When the subject is the patient, target or undergoer of the action, it is said to be in the passive voice (被動語態).
In a transformation from an active-voice clause to an equivalent passive-voice construction, the subject and the direct object switch grammatical roles. The direct object gets promoted to subject, and the subject demoted to object
For example, in the sentence:
The cat ate the mouse, the verb "ate" is in the active voice;
but in the sentence: The mouse was eaten by the cat, the verbal phrase "was eaten" is passive.
Another example of this sentence using active voice:
狗咬了這個男人。
A dog bite(Past ) this man.= "A dog bit this man."
corresponds to this sentence using passive voice:
這個男人被狗咬了 or 這個男人是被狗咬了。
This man bite (Past ) by dog. = "This man was bitten by a dog."


I hope I can help you.

(rewritten from Wekipedia and Yahoo Dictionary)

首先你可以唔從問句去諗，試下諗下一句普通句子先

由主動變被動其實係有rules
present tense現在式ge轉法係
is/am/are + past participle
e.g. I eat an apple --> An apple IS eaten by me.

past tense過去式ge轉法係
was/were + past participle
e.g. I ate an apple --> An apple WAS eaten by me

anita/a taxi / knock down /yesterday
你大概估到個意思係"昨日Anita被的士撞倒"
主動句:
A taxi knocked down Anita yesterday

"yesterday";係昨日，要用過去式，所以係"knocked"
照上面ge例子，被動句:
Anita WAS knocked down by a taxi yesterday
當普通一句句子要轉做問句時，就要將D is/am/are/was/were 擺0係最頭
就好似He is playing football --> Is he playing football?
被動句變問句都一樣
WAS Anita knocked down by a taxi yesterday

你第二個例子
wood / the horse /make of

點解要用is呢?因為佢無特別指明，所以就當隻horse係0係你面前，呢句說話就好似你指住隻horse黎問咁
被動句:
The horse is made of wood.
被動問句:
Is the horse made of wood?

希望咁樣解釋你會問啦