问题 选择题

有甲、乙、丙、丁四种金属,只有甲在自然界主要以单质形式存在。丁的化合物的水溶液不能用乙制的容器盛放,但可以用丙制的容器盛放。这四种金属的活动性由强到弱的顺序是(     )

A.甲>乙>丁>丙

B.丙>丁>乙>甲

C.丙>乙>丁>甲

D.乙>丁>丙>甲

答案

答案:D

以游离态存在说明化学性质稳定,丁盐的水溶液不能用乙制的容器盛放,说明乙比丁活泼,可以用丙制的容器盛放.说明丁比丙活泼.

只有化学性质稳定的物质才能以单质的形式存在,说明甲很不活泼,丁盐的水溶液不能用乙制的容器盛放,但可以用丙制的容器盛放,说明乙可以制取出丁,排在丁的前面,丁比丙活泼,所以乙>丁>丙>甲.

故选D

单项选择题
阅读理解

All over the world, libraries have begun the Herculean task of making faithful digital copies of the books, images and recordings that preserve the intellectual effort of humankind.  For armchair scholars, the work promises to bring such a wealth of information to the desktop that the present Internet may seem amateurish in retrospect. …

Librarians see three clear benefits to going digital.  First, it helps them preserve rare and fragile objects without denying access to those who wish to study them.  The British Library, for example, holds the only medieval manuscript of Beowulf in London.  Only qualified scholars were allowed to see it until Kevin S. Kiernan of the University of Kentucky scanned the manuscript with three different light sources (revealing detail not normally apparent to the naked eye) and put the images up on the Internet for anyone to peruse (阅览).  Tokyo’s National Diet Library is similarly creating highly detailed digital photographs of 1,236 woodblock prints, scrolls and other materials it considers national treasures so that researchers can scrutinize them without handling the originals.

A second benefit is convenience.  Once books are converted to digital form, patrons can retrieve them in seconds rather than minutes.  Several people can simultaneously read the same book or view the same picture.  Clerks are spared the chore of reshelving.  And libraries could conceivably use the Internet to land their virtual collections to those who are unable to visit in person.

The third advantage of electronic copies is that they occupy millimeters of space on a magnetic disk rather than meters on a shelf.  Expanding library buildings is increasingly costly.  The University of California at Berkeley recently spent $46 million on an underground addition to house 1.5 million books – an average cost of $30 per volume.  The price of disk storage, in contrast, has fallen to about $2 per 300-page publication and continues to drop.

小题1:The best title for this passage would be __________.

A.Three Benefits of Libraries

B.Libraries Going Digital

C.Space-saving E-learning

D.Security of Electronic Reading小题2:Which paragraph(s) in the text offer(s) further explanation of the central idea?

A.Paragraphs 2, 3 and 4

B.Paragraphs 3 and 4

C.Paragraphs 2 and 4

D.Paragraph 4小题3:Which one of the following is mentioned as the advantages of E-libraries

A.Old manuscripts can be moved more easily

B.Materials can be examined without being touched

C.Fewer staff will be required in libraries

D.Libraries will be able to move underground小题4:What does the word ‘scrutinize’ probably mean?

A.keep for a while

B.reprint

C.restore

D.examine carefully