Grammar: the modal verbs & the Passive

• Here's a list of the modal verbs in English:
  

can	could	may	might	will
would	must	shall	should	ought to

Modals are different from normal verbs:

1: They don't use an 's' for the third person singular.
2: They make questions by inversion ('she can go' becomes 'can she go?').
3: They are followed directly by the infinitive of another verb (without 'to').

 Learn more here

• How to make the Passive in English?

An active sentence like I drank two cups of coffee has the subject first (the person or thing that does the verb), followed by the verb, and finally the object (the person or thing that the action happens to).
So, in this example, the subject is 'I', the verb is 'drank' and the object is 'two cups of coffee'.

We don't always need to make sentences this way. We might want to put the object first, or perhaps we don't want to say who did something. This can happen for lots of reasons. In this case, we can use a passive. Two cups of coffee were drunk (we can add 'by me' if we want, but it isn't necessary).

We make the passive by putting the verb 'to be' into whatever tense we need and then adding the past participle.
 For regular verbs, we make the past participle by adding 'ed' to the infinitive. So play becomes played. Click here to learn about irregular verbs.

Learn more here

http://www.perfect-english-grammar.com/