Where to put the 了
Okay it is everyone's favorite: another 了 placement question.
First, where would I put a 了 in the following instance if I want to indicate past tense (or completion of an action as it is sometimes referred to)?
Do I put the 了 after the 试图 or the 买?
Second, if 给 is used as a verb, can 了 follow it?
For example: 我给了他五百块。
I'm guessing I can, but because 给 is usually a preposition, I somehow feel weird putting a 了 after it.