He will be here <in/within> a minute

[ryon]

I can't make out the difference between 'within' and 'in'

This is a kind of sentence typically found in the English grammar book.

It is ten to eleven. He will be here ( ) a minute.​

The answer is 'in'.
I don't know why 'within' is not correct for the blank.

Could anyone tell me what the difference is?

 

[majlo]

1. The building will have been built in two years.
2. The building will have been built within two years.

1. it means that it will take two years to build it from now on
2. it means that it will take two years to build it and that's it; we don't know when it will start

Do you understand?

 

[river]

within = inside not beyond a period of time {He'll be here within the hour}.
in = at the end of a particular period {He'll be here in one hour}.

 

[ryon]

THANK YOU, Majio & River!!
Now I completely understand!!

 

[elroy]

1. The building will have been built in two years.
2. The building will have been built within two years.

1. it means that it will take two years to build it from now on
2. it means that it will take two years to build it and that's it; we don't know when it will start

Do you understand?

I don't think I agree with this distinction.

Sentence #1 above tells us that in two years (that is, on March 5, 2008) the building will have been built.

Sentence #2 tells us that sometime between now and March 5, 2008, the building will have been built.

In neither sentence are we told anything about when construction will start or how long it will take.

With the future perfect (as in your examples), the sentences are in essence saying the same thing.

The difference is clearer with the future simple.

1. He will come in an hour.
(If it is 9:21, he will come at 10:21.)

2. He will come within the hour.
(If it is 9:21, he will come at anytime between 9:22 and 10:21.)

 

[panjandrum]

1. The building will have been built in two years.
2. The building will have been built within two years.

1. it means that it will take two years to build it from now on
2. it means that it will take two years to build it and that's it; we don't know when it will start

Do you understand?

Rome wasn't built in a day.

I have yet another view on these two sentences.
There is some confusion in my mind because I hear "will have been built" as relating to the building process. So both sentences relate to how long the building process will have taken - irrespective of when the building is completed. So, I could be talking to you about the major new entertainment complex that is opening down the road from me next week.

It is a different matter if I change the sentences to say:
1. The building will be finished in two years.
2. The building will be finished within two years.

I understand those to mean essentially what Elroy describes above.

 

[elroy]

Rome wasn't built in a day.

I have yet another view on these two sentences.
There is some confusion in my mind because I hear "will have been built" as relating to the building process. So both sentences relate to how long the building process will have taken - irrespective of when the building is completed. So, I could be talking to you about the major new entertainment complex that is opening down the road from me next week.

Good point. I guess there's ambiguity because we don't know whether "will have been built" refers to the process of construction or the finished state.

Would you lean more towards my interpretation (and that of your couplet of sample sentences) if we moved the modifier to the beginning? I think I would.

In two years, the building will have been built.
Within two years, the building will have been built.

(Note: I really don't like "within two years" with "will have been built.")

 

[panjandrum]

Leaning so far in the direction of your interpretation as to be almost horizontal

Isn't it strange how that makes the sentences feel different. I suppose it's because the focus has shifted to the time definitions - which are heard as two years from now.