下列叙述正确的是（ ）
【分析】A、根据高锰酸钾在加热条件下生成锰酸钾、二氧化锰和氧气，进行分析判断。
B、工业上分离液态空气制取氧气的原理，进行分析判断。
C、根据自然界中植物通过光合作用的原理，进行分析判断。
D、根据人体呼出的气体的成分，进行分析判断。
【解答】解：A、该化学方程式缺少反应条件，正确的化学方程式为
故选项说法错误。
B、工业上分离液态空气得到O2，利用的液态氮和液态氧沸点的不同，没有新物质生成，属于物理变化，故选项说法错误。
C、自然界中植物通过光合作用吸收CO2，释放O2，故选项说法正确。
D、人体呼出的气体中CO2的含量占4.5%左右，氧气含量为16%左右，人体呼出的气体中CO2的含量比O2低的多，故选项说法错误。
故选：C。
【点评】本题难度不大，了解氧气的工业制法、光合作用的原理、人体呼出的气体的成分等是正确解答本题的关键。
Dogs are the best pets of humans. They come in all sizes. Some dogs are as small as a football, and others are as tall as a desk. Dogs’ fur (毛) is different, too. It can be long and soft, or smooth and hard. People don’t mind the kind of fur, because all dogs are good to hug.
请在字典中查一下这个词。
我喜欢甜食， 你知道的。
去年， 彼得在旅途中和许多人交了朋友。
我叫托尼· 史密斯， 史密斯是我的姓。
我们在课上回答问题时应该起立
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