1. Chinese verbs do not have inflection in form,the particle “着(zhe) ，了（le ），过(guo)” is often followed by a verb to indicate various additional meanings.However,not every verb can take “着(zhe) and 了(le ) . 2.the aspectual particle 了（le ）is suffixed to the predicate verb ,indicating the completion of an action.The basic patten is as follows: subject+ predicate(verb)+（le ）+ (object) ex.他成功了。(ta cheng gong le ) he succeeded. 2.The negative form of the perfect aspect of an action is：没(mei)+predicate(verb) Note that the aspectual particle 了（le ）after the predicate verb should be dropped in the negative sentence. ex. 我没结婚。（wo mei jie hun）I'm not married. ex.他没成功。（ta mei cheng gong ）He didn't succeed. 3.The completion of an action may either take place in the past ,present .The aspectual particle 了（le ）only shows that an action is in the state of completion.If the time is not specifically pointed out , it normally refers to "the present","the time of speaking". It should be specially noted that a time noun or phrase must be used to give a clear time reference.

le = completion marker It has a number of functions all revolving around completion of an action or process, and the arising of new states. The study of "le" is about 2 or 3 units! Here you just have an example of a sentence structure" ......le meiyou? = Are you......yet?...or....Have you......yet? You need to get back to your course book.

In chinese, it means auxiliaries and modal particles.Used after a verb or adjective, said finish. For example, I have asked Lao wang. the old body poor ; hair white. This pair of shoes are too small. Positive tone. WHO : Tomorrow is Saturday and the new year, people were very happy. The promotion or discourage. WHO : hide ; knock it off! duck! That sighs tone. WHO : great! don't be silly, harry!

Most of the time,it is used as a modal particle as "~Wow,~Mm"in english to express a mood.It's only my ideal ,hope it can help U.

It is not so strict on modern chinese,it also ok if you say ""Nǐ jiéhūn méiyou?" whitout "le".sometimes,"le" only to strength the mood of the speaker,meaningless