"The girl heard a bird."
अनुवाद:लड़की ने एक चिड़िया को सुना।
When using ने the verb agrees with the direct object rather than the subject of a sentence. For example
- हमने किताब पढ़ी - we read a book (using पढ़ी to agree with the feminine word किताब)
- तमने पत्र लिखा - you wrote a letter (using लिखा to agree with the masculine word पत्र)
However because we use को here in this sentence there is no direct object and so the verb is default masculine singular. This is just like if there was no object at all for example
- आपने खाया - you ate (no object so we use masculine singular खाया)
So सुना is correct here.