题目

In most parts of the world, many students help their school make less pollution. They join in “environment(环境) clubs”. In an environment club, people work together to make our environment clean.Here are the things students often do.Turn off the water! Do you know that some toilets can waste(浪费) twenty to forty tons of water an hour?In a year, that would fill a small river! In environment clubs, students mend those broken toilets.No-car day. On a no-car day, nobody comes to school in a car—not the students and not the teachers! Cars give pollution to our air, so remember:Walk, jum15．解方程：（x-1）2=4（x+1）2．