during (the) three hours

@Me_IV posted:

Which one is correct?

1 I am available during the three hours from now on.

2 I am available during three hours from now on.

Hi, Me_IV—Neither one is correct. I think you may be trying to say this:

(3) I am available for three hours, starting now.

It's interesting. Why is neither correct? I think this is correct.

I've been reading/playing/doing something during the last four hours.

Why can't DURING be used in my original sentences?

@Me_IV posted:

Why is neither correct? I think this is correct.

I've been reading/playing/doing something during the last four hours.

"During" is very unnatural and nonnative there. Use "for" instead: "I've been reading for the last four hours."

@Me_IV posted:

Why can't DURING be used in my original sentences?

Grammatical or not, your sentence is hideously unnatural. Use "for the next __ hours." No native speaker would ever say "during the ___ hours from now on."

I agree with David. In the future, Me_IV could say:

- I'll be available for the next three hours.