You first, Navi.
1-Their work should be over by the time we arrive.
2-Their work has to be over by the time we arrive.
3-Their work must be over by the time we arrive.
4-They should finish their work by the time we arrive.
5-They have to finish their work by the time we arrive.
6-They must finish their work by the time we arrive.
Which of the above express:
a-an inference and the idea of likelihood (their work will very probably be over by that time)
b-an obligation (it is their obligation to finish their work by that time)
You first, Navi.
OK. Challenge accepted!
I would say the ones with "should" could mean either that there is an obligation for the work to be finished by that time or that is it likely that it would be finished by that time.
To me, "5" and "6" only carry the idea of obligation. I am less sure about "2" and "3". I would say that in general they would convey the idea of obligation, but maybe by stressing "has to" and "must" one could make the sentences express the idea that it is highly likely that the work would be finished by then.
Last edited by billmcd; 12-Dec-2012 at 22:41. Reason: Addendum
Thanks a lot Bill for the detailed reply,
Azz is my girlfriend. She must have logged in and forgetten to log out! She rarely visits the site. I just thought things were as I had left them on the computer, but apparently she has come to the site.
PS. Apparently it was my mistake. I used the Mozilla engine while normally I use IE. She uses that one and she stays logged on. I did not know that. Sorry. In any case, I take full responsibility for the mistake.
Last edited by navi tasan; 13-Dec-2012 at 02:00.
We will try not to create this kind of confusion again.