1. How long 1.-How long does it take him to do his homework?
Question word
Aux (1st verb)
or iT
2nd verb
Rest
1.If is am are is in the sentence USE it as your AUX/first verb.
2. If there is only one verb, USE DO/DOES/DID
1.-How long does it take him to do his homework?
1. It takes him 1 hour to do his homework (Present simple 3rd p)
2. How long did it take him to do his homework?
2. It took him 1 hour to do his homework (Past simple)
3.-How long will it take him to do his homework?
3. It will take him 1 hour to do his homework (Future 1)
4.-How long is it taking him to do his homework?
5. It is taking him 1 hour to do his homework (Present Continuous)
5.-How long has it taken him to finish his homework?
4. It has taken him 1 hour to do his homework. (Present perfect)