Question

Fill in the blank with a suitable modal with the help of the hint in the brackets:
"I'm working 16 hours a day."
"I think you _______ talk to your boss." (advice)

• A. have to
• B. can
• C. mustn't
• D. should

Answer 1

The correct option is D should

Answer : D

Let's take a look at the usage of the modal verbs in the options:

• have to : It is used to express an external obligation in positive sentences and removing an external obligation (or necessity) in the negative sentences
• can : It is used to express an ability or lack of an ability / to give permission or express a prohibition / to make an informal request / to express a general possibility (only with positive verb) / to make a negative deduction
• mustn't : It is the contracted form of 'must not'; it is used to talk about things we need to avoid
• should : It is used for expressing an opinion / advice / expectation / criticism about some past action or it can be used to ask for an advice

Here in the question, we see that the speaker is expressing an advice, that is to talk to the boss regarding the long work hours.

• As it is an advice & NOT a necessity or obligation -- "have to" is NOT appropriate.
• "can" is NOT appropriate because it is not used to make an advice.

• "mustn't" is used to express that something needs to be avoided, if we use it here it would completely change the meaning of the sentence.

Therefore from among the options, 'should' is the most suitable verb to complete the sentence.

Thus, the correct complete sentence is:

"I think you SHOULD talk to your boss." (advice)