问题 选择题

将石墨置于熔融的钾或气态钾中,石墨会吸收钾而形成称为钾石墨的物质,其组成是C8K、C24K、C36K、C48K和C60K.在钾石墨中,钾原子把价电子交给石墨层,但在遇到与金属钾易反应的其他物质时还会收回.在钾石墨中,钾元素处于石墨层中间,因而石墨层之间被胀大,层间的距离增加.下列对钾石墨的叙述中正确的是(  )

A.钾石墨是一类离子化合物

B.钾石墨导电性比石墨弱

C.钾石墨与水相遇不发生任何反应

D.题干中的5种钾石墨属于同素异形体

答案

答案:A

单项选择题
阅读理解

New archaeological discoveries suggest that trade between Europe and Asia along the Silk Road probably began in some form many centuries earlier than once thought. The findings, coupled with a widening range of scientific and historical research could add a fascinating new page to the epic (史诗) of the Silk Road.

The most surprising discovery is pieces of silk found in the hair of an Egyptian mummy from about 1000 BC, long before regular traffic on the Silk Road and at least one thousand years before silk was previously thought to be used in Egypt. Other research may extend human activity along this route back even further, perhaps a million years to the migration of human ancestors into eastern Asia.

The official origin of East-West trade along the road is usually placed in the late 2nd century BC when an agent of the Chinese Emperor Wu-di returned from a dangerous secret mission(使命)across the desert into the remote high country of Central Asia. The agent, Zhang Qian, travelled as far as Afghanistan and brought back knowledge of even more distant lands such as Persia, Syria and a place known as Lijien, perhaps Rome. Historians have called this one of the most important journeys in ancient times. His journey opened the way for what have been thought to be the first indirect contacts between the ancient world’s two superpowers, China and Rome. Chinese silk, first traded to central Asian tribes for war horses and to the Parthian for acrobats and ostrich eggs, was soon finding its way through a network of merchants to the luxury (奢侈品) markets in Rome.

But the new discoveries show that Chinese silk was apparently present in the West long before the Han emperor started organized trade over the Silk Road. The research could change thinking about the early history of world trade and provide insights into the mystery of just how and when Europe and the Mediterranean lands first became aware of the glorious culture at the other end of Eurasia.

小题1:The word “coupled” in the first paragraph could best be replaced by        .

A.combined

B.contributed

C.doubled

D.produced小题2:The silk thread found in the hair of an Egyptian mummy suggests that         .

A.Egyptians had probably travelled to China to buy silk

B.new light can now be thrown on ancient trading practices

C.historical research often achieves fascinating results

D.trade along the Silk Road began earlier than once thought小题3:Until recently historians mostly believed that trade along the Silk Road       .

A.began a million years ago

B.primarily benefited the Egyptians

C.originated in the 2nd century BC

D.extended human migration into eastern Asia小题4:Historians have always considered Zhang Qian’s mission important because they believe       .

A.he discovered the Silk Road

B.he helped establish East-West trade

C.he travelled as far as Afghanistan

D.he brought back knowledge of Rome to the emperor