Many people use wood stoves and fireplaces to heat their homes．S

Many people use wood stoves and fireplaces to heat their homes．Scientists have become worried about the smoke that they give off．Harmful chemicals are in the smoke．The smoke is causing air pollution．The pieces of pollution,called soot,are floating in the air．They are too tiny to see．Scientists must use a microscope to see them. Small amounts of soot are safe,but large amounts can be dangerous．The govenment wants to limit this kind of pollution．It may stop people from using their fireplaces. The air is tested every day．When soot levels are high,more than 65 micrograms of soot per cubic meter,factories must stop making smoke．The government thinks that limit should be much lower. Factories produce the most smoke and soot．But the government thinks that all types of burning should be limited．The soot levels from factories and homes could be limited．Home owners may have to install new wood stoves that they comply with the new law．Or,they may not be able to bum on days when the air quality is bad. Residents of some towns are fined if they violate the burning ban．Scientists hope these new regulations will make the air cleaner and less harmful to breathe. Why is it dangerous to burn too much wood?
A、The fire could burn yo
B、It's not healthy to be too war
C、Harmful chemicals are released in the so
D、The smoke is filled with un see able tiny piece
【正确答案】：C
【题目解析】：文章首先提到了很多人使用木柴炉和壁炉来取暖，但是科学家们对它们排放的烟雾表示担忧。接着明确指出，这些烟雾中含有有害化学物质，这些化学物质导致了空气污染。文章进一步描述了烟尘（soot）作为污染物的存在，并强调它们由于太小而肉眼看不见，需要显微镜才能观察到。 文章还提到，小量的烟尘是安全的，但大量烟尘可能是危险的。这里的“危险”一词指的是烟尘中的有害化学物质。 现在我们分析选项： A. The fire could burn you（火可能会烧到你） 这个选项与文章主题无关，文章讨论的是烟尘中的有害化学物质，而不是火本身。 B. It's not healthy to be too warm（太温暖不健康） 这与文章讨论的主题无关，文章讨论的是燃烧木材产生的烟尘及其中的有害化学物质。 C. Harmful chemicals are released in the smoke（烟雾中释放出有害化学物质） 这个选项直接对应了文章的主题，即燃烧木材产生的烟雾中含有有害化学物质，这是烟尘被认为是危险的原因。 D. The smoke is filled with unseen tiny pieces（烟雾中充满了看不见的小颗粒） 虽然这个选项描述了烟尘的一个特性（即看不见），但它没有解释为什么燃烧太多木材是危险的。危险的原因是这些小颗粒中含有有害化学物质。 因此，根据文章内容和各个选项的分析，最符合题目“为什么燃烧太多木材是危险的”答案是C，即“Harmful chemicals are released in the smoke”。