Решение:
Для сравнения животных используем сравнительную степень прилагательных.
- The bear is less friendly than the cheetah.
- The cheetah is more aggressive than the bear.
- The bear is stronger than the cheetah.
- The cheetah is faster than the bear.
- The bear is less intelligent than the cheetah.
- The bear is bigger than the cheetah.
Ответ: 1. less friendly, 2. more aggressive, 3. stronger, 4. faster, 5. less intelligent, 6. bigger.