描述地球环境变化 — 英语填空题
题目
Read and fill. Earth is changing. Ten years ago, the river near our school was clean and the air was fresh. But now, because of too much rubbish and smoke from cars, the river is d____ and the air is not f____. The Earth is our only home. We should p____ the Earth, not pollute it. (首字母已给出，每空一词)