Can

Can is a modal auxiliary verb. We use can to:

• talk about possibility and ability,
• make requests,
• ask for or give permission.

Structure of Can

                                      subject + can + main verb

The main verb is always the bare infinitive (infinitive without "to").

 

Notice that:

• Can is invariable. There is only one form of can.
• The main verb is always the bare infinitive. We cannot say: I can to play the piano

Use of Can

We use can and can’t :

• To talk about ability: Tom can speak two languages; I can’t dance, but my brother can.

• To say that something is possible or impossible:

                   Learning Russian can be difficult [= Learning Russian is sometimes difficult.]
                   Children can be very naughty [= Children are sometimes very naughty.]
                   It’s still light. It can’t be bedtime.  

• For requests and refusals of requests

                 Can I open the window  now?
                 You can open the window whenever you like.
                 You can borrow the motorbike today, but you can’t have it tomorrow.

• To offer to help someone:

                Can I help you?
               Can I carry that bag for you?

EXERCISES:

https://elt.oup.com/student/englishfile/elementary3/grammar/file05/grammar05_01a?cc=global&selLanguage=en

https://elt.oup.com/student/englishfile/elementary3/grammar/file05/grammar05_a02?cc=global&selLanguage=en

VIDEOS

This is a short video (3 minutes with very good examples)