Question

(a) She has sung a song.​

Answer 1

Answer:

A song has been sung by her.

Explanation:

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Answer 2

A song was sung by her.

Explanation:

• "Sung" is the past participle used only after a verb to help.  
• Participles are words made up of verbs. Present participles always end up in-ing and function as adjectives. They help to form progressive tenses of verbs. Past participles end up in-ed, or other past tense, irregular verb endings, and function as adjectives. They also combine to create passive verb forms with the verb.
• The auxiliary verbs of past participle, such as “has,” “have,” “had,” and in some cases “would have,” or “should have,” to describe the perfect or conditional aspect of the action.

To know more:

She has sung a song(voice change) - Brainly.in

brainly.in/question/3372073

she has sung two song convert into direct speech​ - Brainly.in

brainly.in/question/11024381