了 - where to put?

[Saturday]

I've been finding it rather difficult to know where in a sentence I should put the "了". And I haven't really got a proper explanation on the subject when asking teachers and friends.

So, not. Once and for all. Can someone please tell me the difference in putting the 了 directly after the verb, and putting it at the end of a sentence.

Take these two sentences for example:

你昨天去哪儿了?

去参加了一个中国的朋友的婚礼。

Why do you put the 了 in the end in the first sentence, but directly after the verb in the second one.

[imron]

See here. Please add any remaining questions you have to the end of that thread once you have read through it all. Incidentally, that thread could have been found by looking in the "All "Simple," yet confusing grammar rules" sticky.