1. _________ air is one of the many problems we have to solve 2. I’ll be in trouble if I _________my passport 3. If it is raining this evening, I_________. 4. We couldn’t go on a picnic as planned __________ it was raining 5. If he ________ hard today, can he have a holiday tomorrow? 6. Because there _________ no buses, we had to take a taxi 7. We plan to ________ this Saturday. 8. I’ll have to buy a map _________ I don’t know this area. 9. If you know where she lives, please let me__________ 10. Life today is very different ______ life 50 years ago. 11. My uncle is a ______. He often does research in his laboratory. 12. My father arrives in Singapore ______Monday evening. 13. I hope the weather will be nice ______ the weekend. 14. Would you like ______ to a party on Saturday? 15. Helen is always in the kitchen. She enjoys ______. 16. Vietnamese women prefer to wear modern clothing ______ work 17. He ______ with friends in an apartment in HCMC since last week. 18. My mother said she ______ busy then