Answer:
1. Negative: He doesn't go to market. Interrogative: Does he go to market?
2. Negative: Ram doesn't pluck mangoes. Interrogative: Does Ram pluck the mangoes?
3. Negative:You don't sing a song. Interrogative: Do you sing a song?
4. Negative: They don't play in the garden. Interrogative: Do they play in the garden?
5. Negative: I don't write a letter. Interrogative: Do I write a letter?