Please help me!

[Anonymous]

Hi, I'm a Japanese student.
Could somebody who speak English as the mother tongue tell me if these rules are correct or not?

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For general ability in the past, we use "could" or "was/ were able to", and
to say that the ability or opportunity resulted in particular action, we don't use "could", but "was/were able to".


We use "must" when the necessity is inside the speaker and "have to" when the necessity is outside the speaker.
"I/we must" can also express a wish.
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And I'd like to ask you.....

(If these English rule is not correct,)Does "must" sound stronger than "have to"?
Is there any difference between "be obliged to" and "be required to"?
As for "must" and "had better", which has stronger meaning of obligation?


My English is so poor. Please help me!!
I'd be glad if you could tell me which country you are from.

Thanks a lot!

[Rusty]

Could somebody who speaks English as the mother tongue tell me if these rules are correct or not? (Hello YUKI. English is my mother tongue. I will tell you what "sounds right").

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For general ability in the past, we use "could" or "was/ were able to", and
to say that the ability or opportunity resulted in particular action, we don't use "could", but "was/were able to".
(These examples all sound OK.
1.He could swim 500 yards when he was ten years old.
2.He was able to swim 500 yards when he was ten years old.
3.He could not swim 500 yards when he was ten years old.
4.He was not able to swim 500 yards when he was ten years old).

We use "must" when the necessity is inside the speaker and "have to" when the necessity is outside the speaker. (This doesn't sound right.
These examples are OK.
I must/have to consider all the details.
I must/have to leave at 8:30 a.m.
All participants must/have to arrive by 9:00 a.m).

"I/we must" can also express a wish. (Yes.
Example: I must look for that book the next time I'm in a book store).
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And I'd like to ask you.....

If these English rules are not correct,)Does "must" sound stronger than "have to"? (I think "have to" is stronger. It also depends on how much you emphasize the word must or have to).

Is there any difference between "be obliged to" and "be required to"?
(Obliged carries a sense of duty. Required means that somebody in authority orders or demands or makes a rule).

As for "must" and "had better", which has stronger meaning of obligation?
(Must has the stronger meaning when had better is meant as a suggestion. Had better can be emphasized and meant as a threat. In this sense, it is stronger than must).

My English is so poor. Please help me!! (You are doing very well!)
I'd be glad if you could tell me which country you are from. (I live in the USA).

[Anonymous]

Thank you very much!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I really appreciate it!!