1. Did he arrive2. Have you explored3. Were cooking, was tyding4. I will take5. Decided6. Study, will pass7. Listened8. Will be 9. Was watching10. If I go, I will take11. Has been working12. It will get13. Was reading, when he heard14. Do people live ?15. I've been learning 16. If the weather is good, we will go for a walk17. If people invent, will not pollute