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46、What is the author’s attitude?


47、The best title for the passage may be ．


48、根据以下材料回答第 1～4 题：
Passage Four
Lawn tennis is a good sport，being based on the ancient game of court tennis，which probably came up in Egypt or Persia some 2500 years ago．Major Walter Wing fieidthought that something like court tennis could be played outdoors on lawns，and in December 1873，he introduced his new game，which he called Sphairistike，at a law party in Wales．The sport became popular very rapidly，but the strange，difficult name disappeared almost at once，being replaced by the very simple and logical term“lawn tennis”．
By 1874 the game was being played by British soldiers in Bermuda，and in the early months of that year a young lady named Mary Outerbridge returend from Bermuda to New York，bt inging with her the equipment necessary to play the hew game．With the help of one of her brothers，she laid out a court on the grounds of the Staten Island Cricket and Baseball Club，and there，in the spring of 1874，Miss Outerbridge and some of her friends played the first game of lawn tennis in the United States。
And just two years later，in 1876，the first United States lawn tennis tournament(锦标赛)was held-at Nahant neat Boston．
Mary Outerbridge is important in the history of lawn tennis because ．



49、The new game called Sphairistike appeared in in 1873．


50、Lawn tennis was introduced to the United States in ．


51、The first United States lawn tennis game was played ．


52、根据以下材料回答第 1～4 题：
Passage Five
A new kind of radar has been developed for spaceship travelers．A working laboratory model of a new system of radar that makes use of a beam of light is said to be ten thousand times more accurate than the best comparable system of radar that used microwaves．
The model has shown that this radar system，known as laser－doppler radar，can measure with absolute precision speeds varying from spaceship orbital injection(进入)velocities(速度)of five miles per second down to virtual stops…speeds of less than one ten thousandth of an inch per second．According to the scientists who are developing this system，such fine measures of cdoctiy are of prime importance in space missions．In a rendezvous(对接)between two spaceships，or in a landing approach by a vehicle onto an orbiting space station，a bump could rip open a ship’s skin，or a nudge could knock the station
out of its orbit．
The light-beam radar，which operates at a frequency of trillions(百万兆)of cycles
per second，could easily detect and measure the movement of a vehicle edging up to a satellite space s tation．A control sy stem using so precise a signal as this would allow a huge vehicle to dock a t a space station as lightly as a feather．
Laster-doppler rada ．


53、Laster-doppler radar is especially valuable in space missions because ．


54、Which of the following statements is not true according to the passage ．


55、Implied but not stated is that ．