They sang a song at the party.
Meaning: This means they produced musical sounds with their voices while performing a single piece of music with lyrics at a social gathering.
Choice of Words: Sang is the past tense of the verb sing, which means to produce musical sounds with one's voice. A is an indefinite article that means one. Song is a noun that refers to a piece of music with lyrics. At is a preposition that indicates a position or time. The is a definite article that refers to a specific thing. Party is a noun that refers to a social gathering of people.
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