Question

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Explanation:

• "silently" describes how an action is done, so it's an adverb.
• "blue" describes a noun (like a blue car), so it's an adjective.
• "sing" is an action word, so it's a verb.
• "through" shows a relationship between words (e.g., through the door), so it's a preposition.

Answer:

• silently → adverb
• blue → adjective
• sing → verb
• through → preposition