问题 选择题

下列实验内容中,x(横坐标)和y(纵坐标)的量的变化关系与右图所示的变化趋势相符的是(  )

XY
A.在烧杯中加入碳酸钠固体和稀盐酸验证质量守恒定律反应的时间烧杯内物质的总质量
B.加热一定质量的高锰酸钾加热的时间剩余固体中锰元素的质量分数
C.烧杯内盛放着一定量的硫酸铜溶液向其中加入铁粉加入铁粉的质量烧杯内溶液的质量
D.用过氧化氢与二氧化锰混合制氧气反应的时间剩余物中二氧化锰的质量

A.A

B.B

C.C

D.D

答案

A、碳酸钠固体和稀盐酸反应生成二氧化碳气体会导致烧杯中物质的总质量逐渐减小,反应结束后总质量不再改变,故A不符合题意;

B、高锰酸钾受热生成锰酸钾、二氧化锰和氧气,氧气散逸到空气中,锰元素的质量不变,因此剩余固体中锰元素的质量分数增大,故B不符合题意;

C、向硫酸铜溶液中加入铁粉,产生硫酸亚铁和铜,溶液质量会减少,故C不符合题意;

D、用过氧化氢与二氧化锰混合制氧气中二氧化锰是催化剂,催化剂的质量反应前后不变,故D符合题意.

故选D.

阅读理解

When I was 18, I had a motorbike accident that put me in a coma for three months. The doctors said there was little chance of my coming out of it, but my identical twin, Marcus, didn’t believe them and carried on talking to me. My first words when I came to myself were, “Hello, Marcus. ”Even though I had no memory of my own name, or that the woman crying at my bedside was my mother, I knew Marcus immediately; it was like a genetic(遗传的)memory. just felt close to him.

As weeks went by, I still could remember nothing before the accident. Marcus was the only person I could relate to.

I had to relearn everything, and Marcus helped me. Because of my twin I wasn’t scared of having lost my memory; I believed everything he said. He became my memory, telling me about my school, friends, previous girlfriends and holidays, showing me family photographs, and telling me how perfect I was.

With his encouragement I slowly recovered and tried to become the person everyone around me loved. Then years later, when my memories flooded back, I learned that I was anything but perfect—I was troublesome, selfish, and now very angry with Marcus for having lied to me.

But finally I understood. Out of love, Marcus had chosen not to tell me about my dark side. He wanted me to have a fresh start—and in fact I had one. Thanks to him, I was able to get married and have kids. I’m 46 now, and feel as if I’m in the third stage of my life. I know all there is to know, and wouldn’t want it any other way.

小题1:Which of the following words best describes Marcus?

A.Dishonest.

B.Thoughtful.

C.Careful.

D.Strict.小题2:According to the text, the author_____.

A.felt very close to Marcus when he first woke up

B.didn’t get his memories back until months later

C.had been very popular before the accident

D.remembered nothing but his own name when he first woke up小题3:How did the author feel when he first got his memories back?

A.Angry.

B.Excited

C.Guilty.

D.Lonely.小题4:What was the author’s purpose in writing the text?

A.To tell us the importance of being honest.

B.To explain the meaning of success.

C.To express his gratitude to his twin.

D.To show how he had suffered.小题5:Which of the following would be the best title for the text?

A.My Twin Rewrote My Childhood

B.An Accident Destroyed My Life

C.Family Will Always Be with You

D.Friends Share Everything

单项选择题