Question

Fill in the blank with a suitable verb:
I'm going to bed. I _______ be up early tomorrow.

• A. should
• B. shouldn't
• C. don't have to
• D. have to

Answer 1

The correct option is D have to

Answer : D

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

• 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
• shouldn't : It is the contracted form of 'should not'. It is the negative form of the modal verb 'should'
• don't have to : It is the negative form of 'have to'
• have to : It is used to express an external obligation in positive sentences and removing an external obligation (or necessity) in the negative sentences

Here in the question we see that the speaker is expressing an external obligation, that is to wake up early.

• As it is not an suggestion -- 'should' is not suitable here.
• Also it is a positive sentence & NOT a negative sentence -- therefore 'shouldn't' is not suitable for use either.
• 'don't have to' is used in negative sentences & it removes the external obligation or necessity, but here the speaker intends to express an external obligation of waking up early, which is why he is going to bed.

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

Thus, the correct complete sentence is:

I'm going to bed. I HAVE TO be up early tomorrow.