"I have known him for a long time."

Translation: 我认识他很久了。

[jcreed]

Why isn't the verb 认识 duplicated here as it is in "他们学中文学了很久了" ("they have been studying chinese for a long time")?

[Keith_APP]

Some verbs are composed of a verb base character with a noun base character, e.g. 骑马，打球，吃饭. With these verbs we repeat the verb base character 骑，打，吃.

Some verbs are formed by 2 verb base characters of identical or similar meaning, e.g. 认识，观察，沐浴. With these verbs we usually do not repeat like that, and if we do we repeat both characters e.g. 他观察野生动物已经(观察了)二十年了. Normally it would be regarded as clumsy and unnecessary.

[RobinThor]

The grammar section to this lesson explains three cases: 1 character verbs, 2 character verbs without object, and separable 2 character verbs with object. Why do they not also explain this case (2 character unseparable verb with object) if they put a sentence in the lesson?

[LeiFeiRalf]

I'm confused why 了 is needed here as it isn't a completed action.

[Gabrielle145359]

I think it's to show time duration.
I know 了 is used to show tine duration in the negative (an action has not been done for X amount of time).
I'm not sure whether 了 also shows time duration in the positive (an action done continuously for X amount of time.)

[Erin56137]

From what I have been taught the ending 了 is often used to bring the action into the present; to show that the action is still occurring in the present. It's like saying I've known him a long time instead of I knew him a long time.

[Ralitsa202552]

Technically 认识他很久了 is passable IMO, it might be a tad more conversational, but language is elliptic: what can be omitted usually gets omitted.

[Slade366]

So is this a special meaning of 了 to indicate continued state rather than completed action? How to know the difference? How would you say I knew him for a long time?

[Keith_APP]

Actually in which context we would use simple present tense and say
"I knew him for a long time." ?

[Slade366]

If he died

[lianlaughsalot]

Can 我很久认识他了 be accepted?

[Keith_APP]

Sorry, but no.

[ClaudioAgl1]

Is 我很久了认识他 correct? It seems it is not.

[Keith_APP]

It is not. It wouldn't be too surprising though if people say this occasionally.

[ClaudioAgl1]

谢谢你!

[HakonEnger]

Is it allowed to put the object after the duration? 我认识了很久他

[Keith_APP]

No. :-)

[Marosaxamit]

Can I use 我认识他好久了?

[Tyler15393]

I put 我认识了他很久 and it worked but I don't know why. Does anyone have an explanation?

[baharem]

Following

[Elder-Simmons]

The 了 is linked to the verb, which is 认识, so it doesn't matter if it goes immediately after the verb or at the end