Questions 21-25 are based on the following passage:

　　In the Arctic Circle, it is not that Eskimos lack ability or industry, but the surroundings restrict constructive effort to the barest necessities of existence．This retards progress to higher develpment．

　　Agriculture is impossible all along the thousands of miles of the north shore．The only wood is such as drifts in．other than this driftwood, the only available building materials are snow, ice, stone, and bones of animals．All of these have been used for habitations and storage, places, differing in various tribes according to the requirements and skill of the workers．The lack of necessary timbers to build walls and span wide spaces is probably one reason why they construct their houses at least partly beneath the surface of the ground．This device also makers the houses more impervious (不能滲透的) to the cold．

　　Most of us are inclined to think that the Eskimo lives always in an igloo or snow house．This is not entirely true．After the long cold winter, the family is very likely to move, when the weather permits, into a tent sealskin．The actual construction of such a tent is similar to that used by other, more southerly tribes and will be described later．

　　The snow house, however, is an interesting and unique habitation．Our summer campers will not build, with snow, but the delicate art is worth recording and some of our winter camps mountains might try to make snow houses．

　　21．Eskimos’ efforts to build houses ___________．

　　A．result in various building

　　B．a(chǎn)re limited by a hostile environment

　　C．a(chǎn)re restricted by their ability

　　D．retard progress to higher develpmen

　　22．Which of the following about the construction of houses is true?

　　A．Building materials differ from tribe to tribe．

　　B．Building materials are the same for all the houses．

　　C．Building materials are selected according to weather．

　　D．Building materials are decided by skilled workers．

　　23．Why do Eskimos build their houses partly under the ground?

　　A．They like to live under the ground．

　　B．They are short of essential materials for walls and roofs．

　　C．They want their houses less affected by the cold．

　　D．Both B and C．

　　24．In the long winter Eskimos commonly live in _________．

　　A．a(chǎn) snow house

　　B．a(chǎn) stone house

　　C．a(chǎn) storage place

　　D．a(chǎn) tent sealskin

　　25．What does the author think of snow houses?

　　A．Interesting

　　B．Artistic

　　C．Unique

　　D．All of the above

　　Questions 26-30 are based on the following passage:

　　Atlanta:

　　Mostly fair．88-70 0 F．Minneapolis:

　　Mostly cloudy．68-50 0 F．

　　Boston:

　　Partly cloudy．78-61 0 F．New Orleans:

　　Mostly fair．92-73 0 F．

　　Chicago:

　　Thunderstorms likely．82-67 0 F．Philadelphia:

　　Hazy and warm．90-68 0 F．

　　Cleveland:

　　Mostly cloudy．84-68 0 F．Phoenix:

　　Sunny and warm．99-66 0 F．

　　Dallas:

　　Thunderstorms likely．91-75 0 F．Pittsburgh:

　　Partly cloudy．81-64 0 F．

　　Denver:

　　Rain likely．53-43 0 F．St．Louis:

　　Thunderstorms likely．86-70 0 F．

　　Houston:

　　Partly cloudy．90-78 0 F．San Francisco:

　　Mostly fair．73-60 0 F．

　　Kansas City:

　　Thunderstorms likely．73-60 0 F．Seattle:

　　Mostly fair．74-50 0 F．

　　Las Vegas :

　　Sunny and warm．93-56 0 F．Toronto:

　　Rain likely．83-68 0 F．

　　Los Angeles:

　　Mostly sunny．88-60 0 F．Washington:

　　Partly cloudy．88-72 0 F．

　　Miami:

　　Partly cloudy．88-79 0 F．

　　26．According to the forecast,

　　A．Kansas City will be warmer than Toronto

　　B．Temperatures will be the lowest in Seattle and Minneapolis．

　　C．The weather will be fine in most ofthe listed cities．

　　D．More than half of the listcities are cloudy or rain likely

　　27．Among the following four cities．The difference between the afternoon high and the evening low is smallest in

　　A．Kansas City

　　B．Miami

　　C．Atlanta

　　D．Seattle

　　28．Which of the following cities is closest to Miami in weather conditions?

　　A．Boston．

　　B．Atlanta．

　　C．Washington．

　　D．Houston．

　　29．The difference between the afternoon high and the evening low is greatest in ______ ．

　　A．Seattle

　　B．Los Angeles

　　C．Las Vegas

　　D．Phoenix

　　30．The differences between the afternoon high and the evening low are the same in ______ 。

　　A．Chicago．Dallas, Kansas City, and St, Louis

　　B． Atlanta, San Francisco, New Orleans ,and Seattle．

　　C． Cleveland, Dallas, St, Louis, and Washington．

　　D．Pittsburgh, Miami, Houston, and Boston