The document discusses the differences between have to, must, don't have to, and mustn't. Have to is used to express obligations imposed from outside sources, while don't have to expresses something that is not necessary but possible. Must is used for personal requirements or orders given by the speaker, and expresses importance or immediacy. Mustn't is used to prohibit something, similar to expressing a strong recommendation not to do something.

2. HAVE TO AND MUST
 https://youtu.be/_BW-8ob18gw
 Must and Have to in the
affermative and interrogative
forms are used to speaking of
obligations and responsibilities.
Sometimes they can be used
interchangeably, but the
general rule is that
contraddistigue

3. HAVE TO
It used to speak of obligations or
responsibilities imposed from outside, Che
not depends from who's talking - Is it
necessary.

4. DON'T HAVE TO
Do not have to is used to express something that is not
necessary .but 'possible to do if desired, it is not an
obligation. .do not have to is flexible as to have.

5. MUST
It must is used to talk about personal
requirements in a manner similar to Should,
but stronger. It is used when the decision to
do something is taken by the speaker or the
order is given by the speaker. It must is
used in everyday situations when something
important happens and requires immediate
action. must only works in this form.
Examples: "I must do the shopping now."
"You must see this film!" "You must read
this book by the end of the week."
"Must you leave so early?"

6. MUSTN'T
Must not it is used to express something
that is prohibited. The rule says that you use
it when the requirement comes from the
speaker. The use of Should similar too, but
stronger.