In the sentence "I hope you will not turn down my request," the phrase "turn down" is an idiomatic expression most commonly used to mean "reject."
Let's break down the options provided to find the correct synonym:
(a) reject - This means to refuse to accept, agree to, believe, or use something. It is a synonym for "turn down," as both imply saying no to a request or offer.
(b) disclose - This means to make something known, especially something that was previously secret or unknown. It is not a synonym for "turn down."
(c) approve - This means to agree to or accept something. It is the opposite of "reject," so it is not a synonym for "turn down."
(d) find - This means to discover or perceive something after a search. It is not related to the meaning of "turn down."
Therefore, the correct answer is (a) reject .
Using synonyms is an important skill when learning English as it helps you expand your vocabulary and understand the different ways words can be used in sentences. Understanding phrasal verbs like "turn down" can also enhance your communication skills.