Present simple = must/have to Past simple = had to

Modal verbs

1. 
   Present simple = must/have to
   

Past simple = had to
Present perfect = have/has had to
Future simple = must/will have to

2. 
   Mustn’t = it is forbidden to do something
   

Ex; They mustn’t play on the railway track

3. 
   Needn’t = it is not necessary to do something
   

The farmer needn’t/ doesn’t need/ doesn’t have to buy any eggs.

4. 
   didn’t need to +infinitive = it was not necessary to do smth.
   

Ex: They didn’t need to cut any more wood.

5. 
   need’t have + past participle = it was not necessary to do something, but it was done.
   

Ex: You needn’t have bought me a gift.

6. 
   could / might + perfect = it was possible, but it didn’t happen.
   

Ex: Yesterday, there was a terrible accident. The driver could have been killed. (Luckily, he was not)

7. 
   present simple = can / am, is, are able to
   

past simple = could / was, were able to
present perfect = have, has been able to
past perfect = had been able to
future simple = will be able to
future perfect = will have been able to

Conditionals

1. 
   If you …(go) away, please …(wiste) to me
   
2. 
   If she … (be) in I …(give) …it to her. Now it’s to late.
   
3. 
   My aunt … (be able to) help us if she … (be) on time last night.
   
4. 
   If my brother ….(eat) another cake, he … (get) sick soon, that’s why he won’t.
   
5. 
   If you …(heat) water, it boil.
   
6. 
   If we …(go ) to London for our holiday last year. We (see) … The Tower of London.
   
7. 
   I …(speak) to Clement at the party if he…(apologize) what he send to me.
   
8. 
   If I …(know) Rob’s address in New York, I…. (visit) him.
   
9. 
   I thank Diane ….(look) much nicer if she ….(have a new hairstyle.
   
10. 
    She …(look) better if she …(wear) a dress to go to the concert last night.
    
11. 
    John …(not get) such poor marks if he ….(work) harder.
    
12. 
    If Katy ….(be) taller, she ….(play) in the ladies’ volleyball team.
    
13. 
    If the weather …(not be) so bad last week, they …(go) for a excursion.
    
14. 
    If I …(be) George I … (not go) to the concert without a ticket.
    
15. 
    If Teny …(get up) earlier this morning, he …(tidy) the house instead of leaving it for his mother.
    
16. 
    Paul ….(pass) his exams early if he …(work) harder.
    
17. 
    If I ….(not have ) so much work to do I …(go) to cinema tonight.
    
18. 
    My brother …(live) in the USA if he … (have) a work permit.