[Grammar] Questions I've kept a long time

[whsans]

Thanks for reading my question.
I wanted to skip these grammar problems,
but they've been haunting me all the time since then.
Let me give them straight.

1. They are not too old to study English.

I thought this says that They are too young to study English...
I wasn't so sure....Is that right?

How about the following?

2. They are too old not to study English.

I thought that they are old enough to study English...
but on second thought, it can be said that they are old enough so they don't have to study English....
I have no idea at all....What does that mean?

3. Is that the earth is round obvious?
When I read a book on English syntax, it said that this sentence is wrong because 'that-clause' is flanked to the left and the right by the main clause...
So the sentence above(no.3) is grammatically wrong..
How about these following sentences?
Are they grammtically right?
- Is the fact that the earth is round obvious?
- Is the fact obvious that the earth is round?

I almost died of curiosity...please save me from hell....

 

[mayita1usa]

Save you from hell?? Oh no!

1. They are not too old to study English.

I thought this says that They are too young to study English...
I wasn't so sure....Is that right?

Not exactly. In this sentence, "too old" means that they are so old they can't learn anything anymore; "too" creates a negative characteristic. Thus, if they are "not too old", it means they can still learn, so they can still study English.

2. They are too old not to study English.

This one is more complicated, and it is difficult to think of a situation where we would say this! Here's a possible example: If everyone in the country studies English in 8th grade, but these children are in 10th grade and they haven't started studying English yet, you might say it like that. But a better way would be, "They are too old to not be studying English." A different example with the same structure might be, "You're too old to not know how to behave in school!" (Notice that I reversed the order of not to in both examples... It sounds better to me that way.)
Don't worry about this one - you will probably never need to use it!

3. Is that the earth is round obvious?
When I read a book on English syntax, it said that this sentence is wrong because 'that-clause' is flanked to the left and the right by the main clause...
So the sentence above(no.3) is grammatically wrong..
How about these following sentences?
Are they grammtically right?
- Is the fact that the earth is round obvious?
- Is the fact obvious that the earth is round?

Your examples are grammatically correct, but very awkward. This is an example of where native speakers use the pronoun "it" in place of "the fact", to make things simpler:
- Is it obvious that the earth is round?

I hope this helps you sleep better!

(P.S. Normally we say, "I'm dying of curiosity!")

 

[whsans]

Thank God...
When those questions hit on me for the first time...
It was killing me...but I got out of it...
and a few days ago,
they came on me again...
I couldn't sleep at all becuase of them.
I don't know how to thank you enough.
Have a great, great day ;-)