题干

下列关于水的说法中,不正确的有:____(填序号).

①水是由氢元素和氧元素组成的化合物     

②清澈、透明的泉水是纯净物

③合理施用农药、化肥,以减少水体污染   

④将活性炭放入硬水中可使其软化

⑤洗菜、洗衣后的水用来浇花、冲洗厕所

上一题 下一题 0.0难度 选择题 更新时间:2012-06-15 11:17:03

答案(点此获取答案解析)

②④

同类题3

阅读下面短文,掌握其大意,然后从所给的A、B、C、D中四个选项,选出最佳选项。

    As a boy I was always small for my age. I was five years younger than one of my brothers and seven years younger than the other. 1, I often felt left out when their friends came over to 2. I was too 3for whatever they were doing and they didn't want me to listen to their conversations either. More often than not I found myself outside playing  4and feeling forgotten.

    I remember one Spring afternoon I felt especially 5as I sat in the yard behind our house. We lived miles from town and I 6saw my own friends outside of school. I 7my brothers laughing from 8the house and felt a single tear coming down my face. At that moment I saw a large brown dog 9me. He was wagging (摇摆) his tail 10. He greeted me like a long lost11, licking (舔) my hand and sitting beside me on the grass,12he didn't know me. I petted and13this four-legged angel (天使). He let me pour out all my troubles and14my deepest thoughts before he kissed me goodbye. I went back inside feeling happy,15that no matter what life might hold I was loved. I16that the dog was sent in that moment of17to remind me just how much I was loved.

    In truth, nothing brings us greater18than knowing we are loved. Knowing we are loved gives us the19to love others as well. It also helps us to be the people the world meant for us to be. Remember how much the world loves you and share your20with the world.