2.5.9: Past Modals for Single Actions in the Past- The Simple Past Tense

Past Modals for Single Actions in the Past:  The Simple Past Tense

       The past tense of must, have to, and has to is HAD TO.

Had to                Obligation or necessity in the past            Past of must,      have to, and
(hadda)                                                                                                                 has to

                         He had to take his daughter to the hospital
                              last night because she had a high fever.
        He had to change the flat tire on his car last night.
        We had to pay our income taxes last year before April 15^th.
        I had to drive my wife downtown because she is afraid to drive in                 the city by herself.
        My son had to memorize a lot of music for his concert.

________            _______________________________ ____________

Must have + past participle                Past conclusion or supposition only;
(musta)                                                  Never a past obligation: For past
                                                                obligations, use had to.

Sara is a teacher; therefore, she must have graduated from a four-year college.
                                                                                                      (conclusion)
There was some candy on the table and the children were in the room. Now the candy is gone. The children must have eaten the candy.  (conclusion)
She broke her leg playing basketball.  It must have hurt a lot.  (conclusion)
When I came home last night, the house was very clean.  My wife must have done a lot of housework during the day.  (conclusion)

However

While I was driving home, I got a flat tire, so I had to use my spare tire. (obligation)
The boy cut his head badly, so he had to go to the hospital.  (obligation)
The toilet broke last night, so I had to fix it right away.  (obligation)

______________________________________________________________________________

Might have + past participle            Past situation -- maybe it happened,
May have + past participle                maybe it didn't. We don't know for sure,
Could have + past participle             but we do know that it was possible.
(mighta, maya, coulda)

        The student didn't come to class yesterday. She might have gone to the doctor's.  She might have had an accident.  She may have gone shopping.  She could have stayed in bed.  I don't know what happened for sure, but all of the above are possible.

My friend bought a lottery ticket.  He could have had the winning ticket.  I don’t know, but it is possible.

It might have snowed in the mountains last night.  Then again, it might not have snowed. 

My sons might have seen each other this past weekend, but I am not sure.

Could have + past participle        Past ability or capability to do something,
but you chose not to do it. You had the opportunity to do something, but you decided not to do it.

A past possibility that you had an opportunity to do, but you chose not to do.

I lived in Asia for over 5 and a half years, but I never went to Korea. I could have gone there many times, but never did. 

I could have stayed in Europe in 1973, but I decided to return to the United States instead.

I could have become a history teacher if I had wanted to, but I decided to become an English teacher instead.

You could have skipped school today if you had wanted to, but you decided to come.

My wife and I could have gone to a movie last night, but we were too tired and decided to bag it and not go.

_______________________________________________________________________

Should have + past participle                    Past obligation which you didn't
do.  Something was the correct or right action to do, but you didn't do it.  Something was a good idea or thing to do in the past, but you didn't do it.  In other words, you made a mistake.

You were speeding in a car and a policeman saw you and gave you a speeding ticket. You should have slowed down, but you didn't.

You had a test last week, but you didn't study for it and you failed it. You should have studied for it, but you didn't.

My son went outside without his coat in the rain last week and he caught a bad cold. He should have worn a coat, but he didn't.

The students shouldn't have cheated on the exam, but they did.

I should have learned how to type when I was in high school, but I didn’t.  As a result, I am a slow typist.  

America shouldn’t have gotten into a war with Iraq, but it did.

Those boys shouldn’t have teased the new student in the class.  He started to cry and then everyone felt bad for him.

 

Exercise 45:  Change the following sentences to the past, using “had to base form of the verb.”  You will need to change “time” words as well as the verbs.

Example:  He must buy a new computer today because his old one broke down last night.

He had to buy a new computer yesterday because his old one broke down the night before last.

1.  We have to get some medicine for our son so that he will recover from his illness.

 

2.  My sister has to take her car to the garage to have it repaired tomorrow afternoon.

 

3.  Students must do all their homework before they come to school in the morning.

 

4.  Bob has to fix his brother’s bicycle so that he can ride to school next week.

 

5.  Children have to obey their parents when they are young.

 

6.  I must remove the weeds from my garden next spring.

 

7.  You have to do a lot of homework this quarter.

 

8.  The policeman on the corner has to direct traffic every morning this month.

 

9.  The boys have to help their father clean the yard this weekend.

 

10.  His mother must help him with his homework tonight.

 

11.  She has to buy a birthday present for her daughter next week.

 

12.  My friend must have his car repaired this afternoon.

 

13.  The boys’ mother has to prepare dinner for her sons.