Question

Choose an appropriate option to fill in the blank:
You .......... forget what I told you. It's very important
A) shan't
B) needn't
C) mustn't
D) won't

Answer 1

Hint: Traditionally, verbs have been defined as words that express action or a state of being. The infinitive is the most basic form in English, and it can be used with or without the particle to.

Complete answer:
In the above sentence, we have to use a verb that shows something that cannot be avoided because of the word ‘important’ in the sentence. The person cannot forget what has been told to him/her.

Let us look at the given options:
A) shan't: This option is incorrect because ‘shall’ is used with first-person pronouns such as I, we whereas ‘you’ is a second person pronoun. Thus, we cannot use ‘shan’t’ with you.
B) needn't: This option is incorrect because ‘needn’t’ is used to give permission to someone to not do something in the future. It shows that there is no obligation but in the sentence, the use of the word ‘important’ shows that the person has an obligation of not forgetting that he/she was told.
C) mustn't: This is the correct option. The verb 'mustn't' is used to communicate about things we should avoid doing. Since in the above sentence, the person should avoid forgetting what he/she has been told, therefore, this is the appropriate option.
D) won't: This option is incorrect because ‘won’t’ is used to indicate that the person will not do something. It implies that there is no responsibility, yet the usage of the word "important" in the statement implies that the person has an obligation to remember what he or she was told.

Thus, the correct answer is option C) mustn’t.

Note: Go, goes, and went are finite verb forms. Go, going, and gone are non-finite forms. Combinations of these forms with auxiliary verbs, such as was going and would have gone, are also possible. Tense, aspect, mood, and modality expressions are all considered in various configurations.