Your book is thin. It is a thin book.1. My mother is beautiful. She is ...
2. Your class is clean. It is ..
3. My friend is smart. He is ...
4. The building is awesome. It is ...
5. The river is long . It is ...
II. Change into negative sentences.
1. Brother drinks an orange juice.
2. I take a ball from cupboard.
3. They buy some books.
4. She cooks delicious meal.
5. Father goes to office.

Answer:

1. My mother is beautiful. She is a beautiful person.
2. Your class is clean. It is a clean classroom.
3. My friend is smart. He is a smart person.
4. The building is awesome. It is an awesome building.
5. The river is long . It is a long river.

II. Change into negative sentences.
1. Brother drinks an orange juice.
(-) Brother doesn’t drink an orange juice.
2. I take a ball from cupboard.
(-) I don’t take a ball from cupboard
3. They buy some books.
(-) They don’t buy some books.
4. She cooks delicious meal.
(-) She doesn’t cook delicious meal.
5. Father goes to office.
(-) Father doesn’t go to office

hope this helps ^^