From the words lettered A to D below each of the following sentences, choose the word or group of words as it…

Analyze the question: We need the correct form of the word "mature" to fill the gap before the noun "person": "I don't believe that any ____ person would do such a thing."

Concept: The gap sits between "any" and the noun "person," so we need an adjective to describe the person.

Checking each option:

• A. matured is a past-tense or past participle form. It is usually used for things that have ripened or developed, such as "matured wine," and it sounds awkward for a person here.
• B. mature is the base adjective, meaning fully grown, sensible and responsible. "Any mature person" is natural and correct.
• C. maturing means "in the process of becoming mature." It doesn't fit the meaning, because the sentence is saying that no grown-up, sensible person would do such a thing.
• D. matures is a verb form (third person singular), so it cannot come before a noun.

Solution: "I don't believe that any mature person would do such a thing."

Tip: When a blank sits between a determiner (a, any, the) and a noun, look for an adjective. Eliminate verb forms ending in -s, and check whether the -ed or -ing forms really fit the meaning. "Mature person" is a standard collocation to remember.