水被称为“生命之源”，双氧水被称为“绿色氧化剂”常用做催化剂．下列关于它们的说法正确的是（ ）
A．都含有氢气
B．都含有2个氢原子
C．都含有氢分子
D．都含有氧元素
A、水、双氧水是纯净物，不含有其他物质，故A错误．
B、水和过氧化氢的化学式分别是H2O和H2O2，它们的一个分子中含有都含有两个氢原子，不在一个分子这个条件下，这种说法错误，故B错误．
C、水和双氧水中都不含有氢分子，故C错误．
D、水和双氧水中溶质的化学式分别是H2O和H2O2，可见它们都含有由氧元素，故D正确．
故选D．
| 完形填空 | ||||
| Our family finally managed to get together, but in a few days we scattered again to the ends of the earth ,and I will begin my new job in a new city. My family has never been 1 in this way. When I think about the 2 future, my heart felt grayish. When I 3 in the morning, it was raining outside and the sky was as 4 as my mood. My daughter 5 the new skirt that her uncle bought and she flew around the departure hall in the 6 and drew a small and beautiful picture in the dim crowd. The airplane had a good 7 of newspapers, magazines, television programmes, food and drinks. The meal even 8 a serving of Haagen-Dazs ice cream. This small present brightened me up 9 . The gentle smile of the stewardess (空姐) was as beautiful as the 10 after the rain. When I 11 the airplane, the language that entered my 12 was completely different from what I was 13 three hours ago. Although the street lights were as 14 as Allentown's, the different clothes and expressions of the people 15 me that I am in a new world. I stood in the busy streets like Alice 16 the world in a fairy tale. My heart was 17 with puzzlement about the indefinite future and longing for the new life. When I 18 being able to do what I like once more ,that I will make new 19 and that I can enjoy the fun of exploration, I could not 20 to think about starting my new life. | ||||
|