Remember that must as well as expressing strong obligation imposed by the law, is also used as a reminder from the speaker to him/herself that it is necessary to do something – obligation the speaker self-imposes. Have to is a semi modal therefore it can combine with other verbs. Remember have to is used for external obligation, general obligation and strong requirement.
Example number one – strong obligation imposed by the law Road sign on the motorway
Drivers must slow down at the junction.
Example number two – a reminder from the speaker to him/herself to do something
I must remember to buy some milk on the way home from work tonight.
(A reminder from the speaker to him/herself)
I must wash my hair when I get home. (Obligation/reminder from the speaker to him/herself)
Have to expresses obligation/requirements/rules and regulations imposed by external factors
Example
I have to clock in every morning at 9 am (Company rules and regulations/the company I work for requires that I do this)
We have to do a lot of homework every day. (Rules and regulation set by the teacher/we are required to do our homework every day)
Should is a gentler form of obligation when compared with must and have to.
In the hotel
Guests should vacate their rooms by 10 am on the day of departure. (This is a requirement/an obligation set by the hotel)
used with customers or clients who pay you for a service.
CHECK YOUR ANSWERS/EXERCISE SEVENTEEN
Fill the gaps in the following exercise with must, should, have to or had to The use of should in this exercise is for polite obligation and not for advice.
1. I think we ____________________ leave early tomorrow in case there is a lot of traffic.
2. My boss says I ____________________ do overtime for the next month or so.
3. I ____________________ remember to take in the washing before I go out as it looks like it’s going to rain.
4. Hurry up! We ___________________ be at the airport an hour before check-in.
5. When I was at school we ____________________ study Latin as we were told it was the best preparation for learning any language.
6. Before the internet came into being we ____________________ go to the local library and do our research from real books.
7. Before mobile phones were invented, we ____________________ meet people in real life to organise things. It was too expensive to talk at length on the home phone. There were no all-inclusive package deals then.
8. Managers ____________________ review customer complaints and their outcomes.
9. The vet says I ____________________ give the tablets to the dog twice a day for a week.
10. Office manager speaking to his team: Everyone within the team ____________________ actively participate during meetings.
11. Being part of the rugby team is a big commitment. If you have a job, it ____________________ not interfere with practices or meetings.
12. We’ll ____________________ *come up with the money before the end of the month or the bank will repossess our house.
*Come up with = to find a way
CHECK YOUR ANSWERS EXERCISE SIXTEEN
1. I think we should leave early tomorrow in case there is a lot of traffic.
2. My boss says I have to do overtime for the next month or so.
3. I must remember to take in the washing before I go out as it looks like it’s going to rain.
4. Hurry up! We have to be at the airport an hour before check-in.
5. When I was at school we had to study Latin as we were told it was the best preparation for learning any language.
6. Before the internet came into being we had to go to the local library and do our research from real books.
7. Before mobile phones were invented, we had to meet people in real life to organise things. It was too expensive to talk at length on the home phone. There were no all-inclusive package deals then.
8. Managers should review customer complaints and their outcomes. (Company advice) 9. The vet says I have to give the tablets to the dog twice a day for a week. (External obligation)
10. Office manager speaking to his team: Everyone within the team should actively participate during meetings. (This is an example where must/have to can be too harsh.)
11. Being part of the rugby team is a big commitment. If you have a job, it should not interfere with practices or meetings.
(This is softer than must/have to)
12. We’ll have to *come up with the money before the end of the month or the bank will repossess our house.
Must + have to
We can also use must + have to when we make logical interpretations.
Example
Johnny must have to work really hard to pay the huge mortgage he took out to buy that large country house.