题目

在气体参与的反应中，能使反应物中活化分子数和活化分子百分数同时增大的方法是 ①增大反应物的浓度 ②升高温度 ③增大压强 ④移去生成物 ⑤加入催化剂( ) A．①②③    B．①②③⑤   C．②⑤   D．①②③④⑤  答案：C解析:略 The population of the Earth is growing faster. It is important that we look after the Earth. We need it!The Earth gives us a lot of things. We also give the Earth a lot, but some of the things are not good.In nature, when something dies, other animals and plants get food from it. Every animal or plant gives food for other animals or plants. However, animals can’t get food from many of the things that we ‘give’ the Earth. Animals and plants can’t eat metal, plastic and glass. These things will stay in the ground for many, many years.Some rubbish is very dangerous for plants and animals. In some places, many animals live together. One animal makes food for many more animals. If we put rubbish and chemicals in the water, the plankton （浮游生物） can die. If there isn’t any plankton, many animals have nothing to eat.So what can we do? Don’t leave any rubbish in the countryside! Don’t make so much rubbish!【1】The Earth gives us __________.A. food B. rubbishC. chemicals D. pollution【2】When something dies in nature, __________.A. water and grass are pollutedB. plastic and wood become foodC. other animals and plants get foodD. metal and glass stay in the ground【3】We must __________ to look after the Earth.A. put metal in the ground B. use more woodC. keep frogs in the water D. make less rubbish