Ответы к заданию.
1)Your watch is 20 minutes fast.There may be some problems with it.
2)Your parent may be upset but must realise why you're so unhappy.
3)Jane is about the same age as me she must be in her forties.
4)May I borrow your pen?
5)It's getting dark.It must be 8 o'clock already.
6)He may know something about this but I'm not quite sure.
7)Excuse me,may I smoke here.
8)They look almost alike.They must be twins.
9)'Jane hasn't come yet'.Don't worry.She may come later.'
10)If you want to have a well-paid job,you must study English.It may help you in your future career.