1.Fill in each gap with an appropriate preposition. 21. The teacher divided class ________four groups. 22. He provide us ________a lot of useful information. 23. The ground is covered ________trash. You should clear ________all the trash. 24. Raw sewage is pumped directly ________the sea. 25. They are trying to save the animals ________extinction. 26. The world will end ________like a second-hand junk-yard. 27. I am looking forward ________hearing from you. 28. Don’t throw trash ________the water. 2.Give the correct form of the verbs in brackets. 29. If the rice padddies are polluted, the rice plants ________________. (die) 30. If we ________on littering, the environment will become seriously polluted. (go) 31. What _________they ________________if they work hard today? (achieve) 32. If you ________________a chance to study in a foreign country, just take it. (get) 33. Plants ________________if they don’t get the sun and water. (die) 34. I am looking forword to ________________from you (hear) 35. I suggest ________________by bus. (travel) 36. If you don’t study harder, you ________________the final exam. (not pass) 37. She ________________terribly sorry if he dies. (feel) 38. Go with me and I________________you my new car. (show)