问题 选择题

生活在密闭狭小的特殊环境(如潜艇、太空舱)里,氧气会越来越少,二氧化碳会越来越多,因此将二氧化碳转化为氧气,不仅有科学意义,也有重要的使用价值。据科学文献报道:NiFe2O4在一定条件下既能促进二氧化碳的分解又可重复使用。NiFe2O4在此反应中是

A.反应物

B.致冷剂

C.催化剂

D.生成物

答案

答案:C

NiFe2O4在一定条件下既能促进二氧化碳的分解又可重复使用,说明NiFe2O4在将二氧化碳转化为氧气的反应中起到催化作用,做催化剂,故答案选C.

单项选择题

I will always remember my mother’s last few days in this world.

On February 14th, 2000, my class went on a field trip to the beach. I had so much fun. When we returned to school, my teacher told me to go to the headmaster’s office. When I got into the office, I saw a police officer. Suddenly I realized something was wrong. The police officer told me what had happened and we went to pick my sister up. After that, we went to the hospital and waited. Time went slowly. Finally, we got to see our mother. It was terrible.

On the next day, the headmaster came and told my two teachers what had happened. I was taking a rest that day. I knew it had something to do with my mother. I kept thinking that she either died or had gotten better. How I wished that she had gotten better. When my teacher took me outside, my sister ran up to me. She started crying, "She’s gone. Teresa, mommy’s gone. She’s dead. " I couldn’t believe it. We jumped into the car and drove straight to the hospital. Most of my family were there. The silence was terrible. I knew I had to say goodbye.

Today when I look back, I still miss my mother very much, but I know that I will live. My mother was a p mother, who had the biggest heart. My mother was an angel walking on the earth. I will always remember her as living. When someone is asked who their hero is, they usually say someone famous, like Michael Jordan or Britney Spears. When someone asks me who my hero is, I tell them, my mother. My mother lives every day. That is what makes her at rue hero.

The writer must think her mother is a ()woman.

A.famous

B.free

C.rich

D.great

多项选择题