1. Denis has always been interested in wildlife. – T
2. Chemistry is his favourite subject. – F (Biology is his favourite subject.)
3. They discuss some interesting problems three times a week. – F (They meet two times a week.)
4. His school is usual. – F (My school is not usual.)
5. Denis and his friends go to different places where they watch wildlife and study their ecology. – T
6. He hasn't a big collection of books. – F (I have a big collection of books.)
7. Denis keeps a lot of pets at home. – T