Modal verbs

USE	MODALS
ABILITY	Can	Could (past)
POSSIBILITY	Can (general  )	Could	May	Might (less probable than may)
PERMISSION	Can	May (formal)
REQUEST	Can / Could	Will (formal)	May (formal)	Would (formal)
OBLIGATION	Must (imposed by the speaker)	Have to
LACK OF OBLIGATION	Don’t have to
DEDUCTION	Must	Should (less certain)	Can’t
PROHIBITION	Mustn’t	Can’t	May not
ADVICE	Should	Ought to	Might	Could
OFFER	Shall	Would
SUGGESTION	Shall	Would	Should (formal)

 

EXAMPLES                                                                                    USE                                                                                                                                                                                      

1.She can drive a lorry                                                                                         ability  

You don’t have to get up early on Saturday                                                 

3.Look at the snow; it must be cold outside.                                                

4.You mustn’t smoke here.                                                                        
5.I might get a job soon                                                                          

6.Shall we go to the theatre this evening?                                                   

7.Will you please help me with my homework this afternoon?                     
8.You have to be at school at 8:45.                                                             

9.If you want to pass English, you should study hard                              
10. Helen hasn’t come to school since Monday. She must be ill             
11.Can you take me to the bus station?                                                     
12.You may only use a pen during the exam                                              
13. I had to go to school very early when I was in England                    
14.It may not rain again this winter                                              
 15.It’s very cold outside; you ought to wear a coat.