题目

Mg2Cu是一种新型贮氢材料,该物质完全吸氢过程中发生反应的化学方程式为2Mg2Cu+3H23MgH2+X,则X的化学式为（ ）A.MgCu B.CuH2C.Cu D.MgCu2 答案：【答案】D【解析】由质量守恒定律：反应前后，原子种类、数目均不变，反应前镁、铜、氢原子个数分别为4、2、6，反应后的生成物中镁、铜、氢原子个数分别为3、0、6，根据反应前后原子种类、数目不变，则每个X分子由1个镁原子和2个铜原子构成，则物质X的化学式为MgCu2。故选D。阅读短文，按照题目要求用英语回答问题。（请注意问题后的词数要求） My name is Clara. I still remember that chilly December day, sitting in science class. I’d finished a worksheet early and picked up a TIME for Kids magazine. A piece of news caught my eye: NASA was holding an essay contest to name its Mars rover(火星探测器).Before I even knew anything else about it, a single word flooded my 11-year-old mind, Curiosity.     I couldn’t want for the bell to ring so I could get started on my essay. That afternoon, I raced home, sat down at the computer, and typed until my fingers ached. “Curiosity is an everlasting flame that burns in everyone’s mind...”     Five months later, my mom received a phone call, and immediately, a wide smile spread across her face.     On August 5,2012,at 10:31 p.m, the rover named Curiosity touched down safely on the surface of Mars, and I was honored to have a front-row seat in NASA.     Curiosity is such an important part of who I am. I have always been fascinated by the stars, the planets, the sky and the universe. I remember as a little girl, my grandmother and I would sit together in the backyard for hours. She’d tell me stories and point out the stars, Grandma lived in China, thousands of miles away from my home in Kansas, but the stars kept us together even when we were apart. They were always there, yet there was so much I didn’t know about them. That’s what I love so much about space.     People often ask me why we go to faraway places like Mares. My answer is simple because we’re curious. We human beings do not just hole up in one place. We are constantly wondering and trying to find out what’s over the hill and beyond the horizon. 56.How did Clara get the new about the essay contest?( no more than 10 words) 57.Why did Clara have a front-row seat in NASA?( no more than 10 words) 58.What does Clara remember about the time spent with Grandma?( no more than 15 words) 59.What does the underlined phrase “hole up”mean?(1 word) 60.In your opinion, why is curiosity important?( no more than 20 words)