Step 1: Understanding the Concept:
The question requires selecting the correct form of the verb "discard" to function as an adjective describing the noun "things".
Step 2: Detailed Explanation:
The sentence structure is "Find out the \_\_\_\_\_\_\_\_\_ things." Here, the blank needs a word that modifies "things".
The past participle form of a verb can often be used as an adjective.
- "discard" is the base form (verb).
- "discarding" is the present participle, used for ongoing actions or as a gerund.
- "will discard" is a future tense verb phrase.
- "discarded" is the past participle, meaning "things that have been thrown away". This fits perfectly as an adjective describing the things.
The complete sentence is: "Find out the discarded things."
Step 3: Final Answer:
The correct option is (D) because "discarded" acts as an adjective modifying "things", indicating the state of the things.