[解析]
M:I think something is wrong with mister hudson.He's not as cheerful as usual.
W:I don't know what it could be.
M:I heard last week
That his mother had been ill.I wonder if that's the trouble.
W:I doubt that yesterday he told me his mother felt much better.
M:Maybe he has a problem here at work.
W:I don't think that he has any problems with his job.
It's well known that mister hudson is the best worker among us.
M:Perhaps there is some trouble in his home.
W:Well The headmaster phoned this morning.
M:That must be the problem.He's worried about his son.