[英文] Grammar

2)How long have you known her?
2) 你認識了她多久? (答案可能係有時間性的:for 2 year /2 month)
基本理解正確 - 亦可留意下面另一種講法

3)Did you know her before?
3) 你從前認識他嗎? (答案可能係 YES/NO)
雖然基本理解正確
但中文更貼切的表達是
你跟她是否已經認識？
這樣講法會較像一般中文意思(理解)

1)是錯的句法和表達
1)How long have you been known her?
假如就文法規則講這句動詞是被動式(have been known)，但主角/主體(subject)是人(you) - 因此還原非問句是You have been known (by) her.你(人)被(她)認識並不是正常的文意。
因此句子不合理。

假如句子改為
How long have you been knowing her?
這句的動詞是現在進行完成式(present perfect continuous tense)，問法示意是假設你一直跟她有聯絡或維持交往的，跟2)的問法意思有這點分別。回答時用你理解的for x year更貼切 - 意思是由x年前開始至今一直都維持(認識)她。反而2)的意思只求問/示意問你何時認識她，回答時可以是I have known her from n years back.或I have known her from n years ago或I have known her last year.等等按那人實際如何認識她或跟她的關係(認識來源)而決定回答的內容，有不同的可能。

1: 你already認識了她多久?
2) 你認識了她多久? mean may be yes and time; no also possible
3)Did you know her before? means no also possible


1)How long have you been known her?
i will change to
how long have you been knowing her

!,2 3, don't say 2321 !
(1)How long have you been (known) knowing her?
Error::-Knowing her =past perfect continuous tense,Or been known to her=passive
=(OVS)
=She knows you
=She has been known to you
=(OVS)
=You have known her (SVO)Past perfect tense
=(The perfect tenses of a verb are the ones used to talk about things that happened Or began before a particular time,as in She's already left., and I had always loved her." This is past perfect tense;=the present perfect=perfect
=Or have you been known to her
=Have you been to her by you yourself?
=(OVS)
=keep contact
(=time for n years.)

(2)How long have you known her for 2 yrs/2 months?----plural in no.please!
(3)Did you know her before?
before means Yes/no.
(only as GF.)

1)How long have you been known to her?

1) How long have you been known her? ~ wrong (passive voice)

意思不同
How long have you been known by her? ~ passive voice
How long has she known you? 她認識了你多久? ~ much better (active voice)

2) 答案可能係有時間性的 :for 2 years /2 months ~ plural
3) OK