It is Saturday afternoon. Liu Tao and his friend David are taking a walk in the park. There are many public signs in it. They mean different things. Liu Tao knows a lot of things about them. Suddenly, they see a short man walking on the grass. Liu Tao points to the sign on the grass and says to him, "Sir, look at the sign! You can't walk on the grass. "The man smiles and says, "You are right, young man. But I'm the park keeper. I'm looking after the grass. "

反应SiO₂(g)+3C(s)=SiC(s)+2CO(g)     △H>0的叙述中，正确的是（      ）

    夜深了，从一座陈列珍贵字画的博物馆里，突然传出了急促的报警声。警察马上赶来，抓住了一个划破玻璃企图盗窃展品的犯罪嫌疑人。你也许不会相信，报警的不是值夜班的看守，而是被划破的玻璃！这是一种特殊的玻璃，里面有一层极细的金属丝网。金属丝网接通电源，跟自动报警器相连。犯罪嫌疑人划破玻璃，碰着了金属丝网，警报就响起来了。这种玻璃叫夹丝网防盗玻璃  博物馆可以采用  银行可以采用  珠宝店可以采用  存放重要图纸  文件的建筑物也可以采用

    另一种“夹丝玻璃”不是用来防盗的。它非常坚硬，受到猛击仍安然无恙；即使被打碎了，碎片仍然藕断丝连地粘在一起，不会伤人。有些国家规定，高层建筑必须采用这种安全可靠的玻璃。

一个人进食淀粉后，取其胃中的内容物检查正确的结果是（    ）