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Many times when we are trying to say how likely we think something is, we use words like sure, certain, probably and perhaps. But another useful way of saying the exact same thing is to use modal auxiliary verbs, such as may, might and must.

There are many different ways to use the verbs and we will take a look at them now.
 

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MUST, HAVE TO AND CAN´T
 
When we want to say that something is absolutely certain or we are sure about something, we use the modals “must”, “have to” and “can´t”. When we are certain about a positive thing we use must and have to and when we are sure something is not true we use can´t. For example:

~ She must be in the building somewhere, because her car is here.

This means that we are certain she is here for the reason that her car is here.

~ He can´t be in his office, because the light is off.

This sentence means that we are sure he is not in his office because the light is not on.
We can use “mustn´t” or “can´t” for a negative sentence here.

 
SHOULD AND OUGHT TO
 
We can use should and ought to when we want to say that something is probably true. For example:

~ He left about three hours ago, so he should be home by now..

This sentence means that it is very likely that he has arrived home because he left a long time ago. We can also use the word “will” when we are talking about negative ideas. For example:

~ He hasn´t studied for the exam, so he will find it very difficult..

This means that because he hasn´t studied, it is probably going to be very difficult for him to pass the exam.
 

MAY, MIGHT and COULD
 
If we think something is a possibility, it is often better to use the words “may” and “might” instead. Just be careful when using the second conditional, as you cannot use the word “may”. For example:

~ I haven´t seen her for a while, so she might not be here anymore.

This sentence means that because the person hasn´t seen her for a while, it is possible that she is no longer there.
 

USING MODAL VERBS TO TALK ABOUT THE PAST
 
You may have noticed that I have been using everything in the present so far. But it is possible to use these modal verbs to talk about the past as well.
To do this, it is necessary to use the word “have” and a past participle after our modal auxiliary. For example:

~ She must have had a great time on her holiday, because she won´t stop smiling.

Obviously we are sure that she had a great time, because she is very happy now.

~ John left for home about five hours ago, so he should have arrived there by now..

This means that John left a long time ago, so it is safe to assume that he has probably got home by this time.

 
As you can see, modal verbs are very useful when talking about probability. And there is always more than one way to say something important. Try out our example questions and see how you do.

 
K. Charles
 

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