Modal Verbs

       Modal verbs are very common in English. We can use them to express a number of things 

including possibility, obligation, prohibitions and ability. For example:

• It might rain. (possibility)            
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• I can ride a unicycle. (ability)
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• You musn't do that. (prohibition)
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• She must let us know what she things. (obligation)    

      Notice how the infinitive verb following a modal verb has no 'to'. For example:

• They should help us.

• We may stay.

       We form negatives by placing 'not' after the modal verb. For example:

• They should not do it.
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• We may not like it.     

     

       We can make guesses with a modal verb+ "be"+ noun. For example:

• It could be Barack Obama.
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• It can't be George Bush.
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• It must be Barack Obama.