WORD FORM: 42. Many factories still allow ........., such as toxic waste, to flow into our river. (pollute) 43. The government ought to ........ up the rules on river pollution. (tight) 44. Raising gasoline taxes means ....... the burning of fossil fuels. (courage) 45. The local residents got no .......... from the company about the ........ sewage discharge. (respond/treat) 46. Don't be ........ about your coming graduation exam. Just take it easy. (worry) 47. I suggest collecting all the ...... letters, and then send them directly to the head of the committee. (complain) 48. Preventing ........ so that our children know about wildlife. (forest) 49. In order to keep our environment .........., we must solve lots of problems. (pollute) 50. I want everyone to see it ........, please. (clear) GIÚP MÌNH VỚI Ạ!!