Learning how to use modals for necessity and suggestions when travelling.

2. Modal verbs are helping/auxiliary verbs that
express ideas like ability, necessity,
and prohibition.
Many modal verbs have more than one meaning.
They are always followed by the simple form of
a verb.

3. HAD BETTER o 'D BETTER
OUGHT TO
SHOULD
SHOULDN´T

4. 
We can use 'must' to show that we are certain something is true .
In general, must expresses personal obligation.
Ex. We must show our passport at the airport
We often use have to to say that something is obligatory.
In general, have to expresses impersonal obligation
Ex. John has to wear a tie at work.
Children have to go to school
We can use need to say something is necessary
or unnecessary
Ex. You usually need to check in at least two
hours before a flight leaves.
I don’t need to take a raincoat

5. 
We use “had better” to give advice about
specific situations, not general ones.
Ex. You'd better tell her everything.
Is used to advise or make recommendations. also
expresses assumption or expectation as well as strong
probability.Ex. You ought to stop smoking. RECOMMENDATION
This stock ought to increase in value. PROBABILITY
We often use should when offering advice
or opinions .
Ex. You should see the new James Bond movie. It's
great!.
People should worry more about global warming.

6. http://web2.uvcs.uvic.ca/elc/studyzone/330/gramm
ar/330-modals-necessity1.htm