题目内容
根据下列文章,请回答 31～35 题。
Superconducting Ceramic (陶瓷)
An underground revolution begins this winter. With the flip (轻击) of a switch,30,000 homes in one part of Detroit will soon become the first in the country to receive electricity transmitted by ice-cold high-performance cables. Other American cities are expected to follow Detroit's example in the years ahead, which could conserve enormous amounts of power.
The new electrical cables at the Frisbie power station in Detroit are revolutionary because they are made of superconductors. A superconductor is a material that transmits electricity with little or no resistance. Resistance is the degree to which a substance resists electric current. All common electrical conductors have a certain amount of electrical resistance. They convert at least some of the electrical energy passing through them into waste heat. Superconductors don't. No one understands how superconductivity works. It just does.
Making superconductors isn't easy. A superconducting material has to be cooled to an extremely low temperature to lose its resistance. The first superconductors, made more than 50 years ago, had to be cooled to -263 degrees Celsius before they lost their resistance. Newer super conducting materials lose their resistance at -143 degrees Celsius.
The superconductors cable installed at the Frisbie station is made of a ceramic material that contains copper, oxygen, bismuth (铋), strontium (锶), and calcium (钙). A ceramic is a hard, strong compound made from clay or minerals. The super conducting ceramic has been fashioned into a tape that is wrapped lengthwise around a long tube filled with liquid nitrogen. Liquid nitrogen is super cold and lowers the temperature of the ceramic tape to the point where it conveys electricity with zero resistance.
The United States loses an enormous amount of electricity each year to resistance. Because cooled superconductors have no resistance, they waste much less power. Other cities are watching the Frisbie experiment in the hope that they might switch to super conducting cable and conserve power, too.
第 31 题 What is the benefit of the revolution mentioned in the first paragraph？
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while we don’t agree we continue to be friends
根据下列文章,请回答 51～65 题。
What IS Cancer？
Cancer is actually a group of many relateddiseases that all have to do with cells．Cells are the very small。units thatmake up all_______ (1) things，including the human body．There are billions ofcells_______ (2)each parson’s body．
Cancer happens when cells that are not normalgrow_______ (3)spread very fast．Normalbody cells grow and divide and know when to stop growin9．Over time，they alsodie_______ (4)these normal cells，cancer cells just continue to grow and divide outof control and don’t die．Cancer cells usually group together to form. tumors(肿瘤)．
A growing tumor becomes a lump of cancer cells_______ (5)can destroy the normalcells around the_______ (6)and damage the body’s healthy tissues．This can makesomeone very_______ (7)．
Sometimes cancer cells break away from theoriginal tumor and travel to other areas of the_______ (8)。where they keepgrowing and can go on to form. new tumors．This is how cancer_______ (9)．Thespread of a tumor to a new place in the body is_______ (10)metastasis(转移)．Peoplewith cancer may feel pretty sick at times——but can usually still do lots of normalthings．_______ (11)they are very sick，kids and teenagers with cancer may stillbe able to go to sch001．They may be tired or bruise(出现青肿)easily, but they_______(12)sometimes go t0 camp．movies．and sleepover(在外过夜的)parties．People with cancer stilllike the same things they did _______(13)they got sick．
Cancer in kids is rare——but today, manykids who do get cancer go on living normal lives．The number of kids who beatcancer goes _______ (14)every year because of new cancer treatments。So a lot ofkids with cancer will some day drive cars，go to college，have careers，and evenget_______ (15)and have families of their own．
第 51 题
A．whichB．whereC．whatD．when
Nurses who work in the intensive care unit in a hospital are better trained than
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