Complete the sentence: It's not necessary ___ a new dress for the dance.

• A. To buy
• B. Buying
• C. To buying
• D. Bought

Answer: (A)

Using the to-infinitive after “It’s not necessary” is the pattern that shows an action isn’t required. In this sentence, the action is “buy a new dress.” The standard completion is “to buy,” giving: It’s not necessary to buy a new dress for the dance.

The other forms don’t fit because they don’t follow this structure: Buying would need a different construction and isn’t used after “It’s not necessary”; To buying is not a valid combination after this phrase; Bought is a past participle and doesn’t form the correct verb pattern here. You could also say, “There’s no need to buy a new dress,” which uses the same idea with a different phrasing.