MUST or HAVE TO

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
In the positive/affirmative forms, must and have to mean the same (or very similar thing).

In the negative, however, they mean different things :

You mustn't smoke = you have an obligation NOT to smoke
You don't have to smoke = you can smoke if you like but it's not necessary.

MUST stays the same in all persons

I must
You must
He must
She must
We must
You must (pl)
They must

However, you need to conjugate have to:

I have to
You have to
He/she has to
We have to
They have to

For the future, we can use must by using must + specific time

I must go at 6 o'clock tomorrow

BUT for there is NO PAST FORM of MUST so you need to use have to (had to) :

Use must or have to (conjugate if necessary) :

1. Yesterday, I go to London
2. I am going to go to Rome tomorrow
3. To speak good English, you don't be intelligent
4. You n't smoke in public places in France anymore.
5. Why do you go to America ?