Odd problems of using English - mostly vocabulary

[pinkie]

Hello professor,
I have some odd questions about English:

1- What does “to bother to do something” mean? I found it in: “I wouldn’t have bothered to come if I had known.”
2- Is “frame” much different from “framework”? Can I use them interchangeably?
3- “I wouldn’t call on him just yet if I were you.” I don’t understand what just yet means here. Can you give another example in which we can use that phrase?
4- How different are these 2 following sentences?
· Have you been to Belfast already?
· Have you been to Belfast yet?
5- “He said he wished he had been able to see you before he left. He would have liked to say goodbye personally. He hoped you would accept his apologies.” Why is would have liked used here? It should be liked ...
6- “It didn’t take very long to get here. We needn’t have taken a taxi. We could have saved the money we spent and had dinner on the train.”
Why can we use had here? I think the right tense and form is would have had because in fact they did take a taxi, not a train.

I’m studying on my own and I don’t know any other place to find a teacher of English to ask. Thanks a lot in advance.
Pinkie

[Alan]

I'm afraid you'll have to repost these questions separately, giving each an appropriate heading.