Ответ:
ІІІ.
1. The girl learns English - The girls learn English
2. My friend gets up early - My friends get up early.
3. The worker comes home at six - The workers come home at six.
4. My brother works at a factory - My brothers work at a factory.
5. His uncle lives in Poltava - His uncles live in Poltava.
6. The bus runs quickly - The buses run quickly.
ІV.
1. The engineers go to the plant - The engineer goes to the plant.
2. The pupils do their homework - The pupil does his homework.
3. The trees grow well - The tree grows well.
4. The boys go in for sports - The boy goes in for sports
5. My friends study English - My friend studies English
6. The girls sing very well - The girl sings very well.