Chapter 17: Exploring More Important Verb Structures 249
When you add have to a modal verb and then use a past participle (the last
column in verb tables) it shows that the action refers to the past:They must have loved it.
She couldn’t have watched the movie.So the order is: subject plus modal verb plus have plus past participle.Comparing the modal verbs and what they do..............................
So how do you explain the way to use modal verbs? Well you can divide them
up into specific functions.Showing degrees of probability
At times you aren’t certain about something happening, but you want to
make a stab at saying what is the probability or likelihood of it coming to
pass. Some of the modal verbs come in really handy in this case.You can represent each of these modals of probability in the form of a
percentage:✓ Must: He must be happy. It’s about 95 per cent certain he is.
✓ Might: He might be happy. It’s about 60 per cent certain he is.
✓ May: He may be happy. It’s about 60 per cent certain he is.
✓ Could: He could be happy. It’s about 40 per cent certain he is.
✓ Can’t: He can’t be happy. It’s about 95 per cent certain he isn’t.
Notice that must and can’t function as opposites here. You use can to show
ability or permission but not probability.Expressing the future with ‘will’
When you refer to future time you can use will, although to be going to and
tenses such as the present simple and continuous are also possible. (I cover
these tenses in Chapter 16.)In a language course, you usually start with will, often called the future
simple, to teach students how to express the future because it’s pretty easy
to use. You just put will before the infinitive (original or unchanged form of
the verb) and that’s it. For example: I will start tomorrow.Although some people still use ‘shall’ in the future simple, it sounds a little
old fashioned so you really don’t need to teach it for this purpose.