有些句子相当有用,尽量减少语法错误,)it’s everyone’s duty to love and protect the environment.(爱护和保护环境是每个人的责任和义务,以环保话题,trees are very helpful and important for us. (树对我们人类是多么的重要和有用, 尽量围绕环保展开主题,比如:(过渡句)the most important question in the world today is pollution .(当今世界最重要的话题