Ability, Admission and Advice
Basic Modals
Modals verbs modify principal verbs to express various degrees of modality such as necessity, permission, etc. . The most common modals are:
Can
Should
Can I borrow your car?
We should pay attention to the inflation rates.
Modal verbs remain in base form for all subjects.
Positive Form:
Subject + Modal + Verb + objects
Can I borrow your car?
We should pay attention to the inflation rates.
Negative Form:
Subject + Modal + Not + Verb + objects
He can't find a co-signer for his loan application.
You shouldn't just complete the task at your convenience.
Question Form:
Modal + Subject + Verb + objects
Can we barter goods and services?
Should I ask for more than the value at market price?
Can for Ability and Permission
'Can' is used to speak about abilities as well as asking for or giving permission.
Giving Advice with Should
Use 'Should' to ask for or give advice or suggestions.
Ought to, Had Better
'Ought to' and 'had better' express the same idea as 'should'. Although not as common as 'should' both these forms can be used in place of 'should'.
Example:
We had better find a new stockbroker.
You ought to research your tax base.
NOTE: 'had better' is a more urgent form.