题干

下列有关氧气和二氧化碳的说法不正确的是(   )

A:自然界中的氧气和二氧化碳通过光合作用与呼吸作用可以相互转化

B:实验室制氧气和二氧化碳都可通过分解反应制得

C:氧气和二氧化碳都可以用向上排空气法收集

D:一般情况下,氧气能支持燃烧,二氧化碳不能支持燃烧

上一题 下一题 0.0难度 选择题 更新时间:2017-05-21 01:16:54

答案(点此获取答案解析)

B

同类题4

阅读理解

    In 1971 a young man who grew up very poor was travelling across the country, trying to make a new start for himself. Along the way he had completely run out of(用光) money and was forced to spend the night in his car. This continued until one morning, after a week of sleeping in his car, he walked nervously into a restaurant and ordered a big breakfast.

    After eating his first good meal in weeks, he found himself lying to the waiter, telling him he had lost his wallet. The waiter, who was also the owner, walked behind the chair where the young man had been sitting. He bent down, and came up with a $20 bill that looked as if it had fallen on the floor and said, “Son, you must have dropped this,” the owner said. The young man couldn't believe his luck! He quickly paid for the breakfast, left a tip, bought gas with the change, and headed West.

    On the way out of town, he began to understand what the owner did. Maybe nobody dropped the money at all. “Maybe that fellow just knew I was in trouble and he helped me in a way that didn't embarrass(使尴尬) me. So I just made a promise to help other people if I can.”

    Later, he worked very hard and became a rich man. Now he lives near Kansas City. Each year he gives away thousands of dollars. He is known as the “Secret Santa” because at Christmas time each year, he personally hands money out to those on the street and at restaurants. Last year, he gave more than $50,000 away in Kansas City.