Обусловьте в предложениях видовременные формы глаголов и укажите их инфинитив: 1.

1. Cars exhausts pollute the atmosphere. Present Simple (to pollute)
2. What did his last experiment lead to? Past Simple (to lead).  
3. When will you graduate from the University? Future Simple (to graduate).
4. Approximately 350 million people speak English as their native language. Present Simple (to speak).
5. I know that she was teaching chemistry last year. Present Simple (to know), Past Continuous (to teach).
6. He has recently written a scientific paper. Present Perfect (to write).