Which form is correct?
I want to be able to run 3 miles even when I am very old.
I want be able to run 3 miles even when I am very old.
Use the first option, as this Ngram would indicate.
What bothers me, though, is how many instances of “want be able to” I found in published books. I found dozens. Some of them are obvious typos:
If you turn this on and someone has bugged your office and starts to listen to you he will get one awful ear ache, and he want be able to hear a thing you say, all he will hear will be static. [should be “he won’t be able”]
and some are mere coincidence:
Know in advance what buyers want. Be able to deliver anything, however rushed and however special it may be, right on the day the order is received.
For some, though, it’s hard to tell if the want should be won’t, or if the word to was inadvertantly omitted. For example:
Of course, some companies want be able to make late changes on project work.
That could be corrected as either:
Of course, some companies want to be able to make late changes on project work.
Of course, some companies won’t be able to make late changes on project work.
Don’t ask me why so many of those could be found – I want to be able to explain it, but I won’t be able to explain each one.
Source : Link , Question Author : Derfder , Answer Author : J.R.