问题 单项选择题

下列关于石灰的说法错误的是:

A.生石灰通常可以作为食品干燥剂 

B.澄清石灰水放置在空气中易变浑浊 

C.汉白玉与石灰石的主要成分相同 

D.“烈火焚烧若等闲”指熟石灰的高温煅烧

答案

参考答案:D

解析:解析 食品干燥剂一般是无毒、无味、无接触腐蚀性、无环境污染。食品干燥剂是为了降低食品袋中的湿度,防止食品变质腐败;食品中常用的干燥剂是氧化钙和硅胶,蒙脱石干燥剂,氯化钙干燥剂,纤维干燥剂。故A正确。二氧化碳通入澄清石灰水变浑浊,是因为二氧化碳和澄清石灰水反应生成碳酸钙沉淀,化学方程式为:CO2+Ca(OH)2=CaCO3↓+H2O故B正确。汉白玉主要成分是碳酸钙,它是一种化合物,化学式是CaCO3。基本上它并不溶于水。石灰石主要成分是碳酸钙(CaCO3)。石灰和石灰石大量用做建筑材料,也是许多工业的重要原料。故C正确。“烈火焚烧若等闲”指烧炼石灰石,石灰石的主要成分是碳酸钙CaCO3,而熟石灰的主要成分是氢氧化钙Ca(OH)2,二者主要成分不同,故D错误。 故正确答案为D。 考点:生活常识

单项选择题
阅读理解

Dogs may help save the day in the Philippines, as they use their noses to smell out survivors buried by Friday’s mudslide(泥石流). The team of dogs arrived in the Philippines from Spain, and this Tuesday they were just beginning their work. Search officials told CNN they hope the recent rain will wash away the smell of rescue teams so the dogs can do their job more accurately.

The dogs were brought in after sound equipment found sounds coming from deep inside the ruins, at a place where a school stood before the mudslide covered it. The sounds could mean people are still alive under all the mud or it could just be the earth resettling.

On Monday, rescue workers worked at the school site until three in the morning, trying to locate survivors, and they will begin digging again as soon as the dogs think they find someone.

Human teams from the US, Malaysia, and Australia are all trying to help, too. But so far they have yet to locate any survivors. Rescue workers told CNN that an earlier report that 50 survivors had been found was false.

How did all that mud bury the village in the first place? On Friday, 2,400-foot Mt Kanabag turned into a mudslide after two weeks of constant rain weakened it. The mountain crumbled and the mud fell onto the village Guinsaugon, burying the 1,800 people who lived there . Out of the 300 houses in the village, only 3 were not covered by the mud . The village is on a southern Philippine Island called Levte. Rescue efforts have been difficult because the village takes six hours to reach from the nearest airport. Hopefully, the dogs can help their human friends find survivors.

小题1:According to the search officials’ words in the first paragraph, we can learn that_________

A.the smell of rescue teams can disturb the dogs

B.the dogs can follow the smell of rescue teams

C.the gods can’t smell the rescue teams

D.the dogs can tell the differences between people and rescue teams小题2: The main purpose of this passage is probably_______.

A.to show the way to rescue the victims in the ruins

B.to introduce the instruments to save victims in a disaster

C.to tell readers that dogs can smell out victims buried in the ruins

D.to show how to train dogs to save victims in a mudslide小题3:How many survivors were found by the dogs?

A.50.

B.Only a few.

C.1,800.

D.None.小题4:The reason why the rescue work wasn’t going smoothly was probably that_______.

A.the rain was heavy

B.so many people were buried

C.it was difficult to reach the village

D.these is little chance to save the survivors小题5:The underlined word “crumbled” in the last paragraph can be replaced by______.

A.broke

B.shook

C.fell

D.moved