Identifying What the Modal Verb Expresses

The correct answer is “advice.”

 

Modal Verbs are a very special type of verbs because they are always used in the same form – they don’t change to match their subjects. These modal verbs change the meaning of the main verb in some way, often by expressing advice, necessity, ability, expectation, permission, possibility, or an offer or a polite request.  
 

The main verb that follows is always the “bare infinitive form” – the basic verb without “to” before it.
 

It can’t rain on my birthday!
 

We may not be able to have a party!
 

Ought to is considered as a modal verb, but it also has properties of semi-modal verbs.  Like a modal verb, it does not change form; however, like a semi-modal verb, a “to” is required before the main verb.  

Ought to is used to express advice, and functions in a similar manner like “should” with a stronger sense of obligation or intensity.      

I ought to be home by 9:00. (advice—to oneself)