閱讀理解

　　The accuracy of cientific observations and calculations is always at the mercy of the scientist's timekeeping methods. For this reason, scientists are interested in devices that give promise of more precise timekeeping.

　　In their search for precision, scientists have turned to atomic clocks that depend on various vibrating atoms or molecules to supply their "ticking". This is possible because each kind of atom or molecule has its own characteristic rate of vibration. The nitrogen atom in ammonia, for example, vibrates or"ticks" 24 billion times a second.

　　One such atomic clock is so accurate that it will probaly lose no more than a second in 3000 years. It will be of great improtance in fields such as astronomical is a sesium atom that vibrates 9.2 billion times a second when heated to the temperature of boiling water.

　　An atomic clock that operates with an ammonia molecue may be used to check the accuracy of predictions based on Einstein's relativity theories, according to which a clock in motion and a clock at rest should keep time differently. Placed in an orbiting satellite moving at a speed of 18000 miles an hour, the clock could broadcast its time readings to a ground station, where they would be compared with the readings on a similar model. Whatever differences develop would be checked against the differences predicted.

　　1. Scientists expect that the atomic clocks will be ________.

　　a. more precise

　　b. absolutely accurate

　　c. more durable

　　d. indestructible

　　2. The heart of the atomichron is ________.

　　a. acesium atom

　　b. an ammonia molecule

　　c. a nitrogen atom

　　d. a hydrogen

　　3. From theselection, we may assume that temperature changes ________.

　　a. affect only ammonia molecules

　　b. may affect the vibration rate of atoms

　　c. affect the speed at which atoms travel

　　d. do not affect atoms in any way

　　4. Identical atomic clocks may be used to check ________.

　　a. the effect of outer space on an atomic clock

　　b. the actual speed of an orbiting satelite

　　c. the accuacy of predictions based on theories of relativity

　　d. all of Einstein's theories

　　5. Implied but not stated: ________.

　　a. Precise timekeeping is essential in science

　　b. Scientists expect to disprove Einstein's relativity theories

　　c. Atomic clocks will be important in space flight

　　d. The rate of vibration of an atom never varies

　　答案: aabcc

　　翻譯

　　中國橋梁

　　中國的橋梁建設有著悠久的歷史。中國古代橋梁以木材和石頭為主要建筑材料,形式多樣，極富特色。中國現(xiàn)存最古老的橋梁為隋代建造的安濟橋，位于河北省趙縣。安濟橋又名趙州橋，橋長50.82米，橋寬9米，為國家重點保護的文物(cultural relic)。清朝末年，蘭州黃河鐵橋建成，標志著中國橋梁建設進入了以鋼鐵和混凝土(concrete)為主要材料的時期。如今，中國的橋梁建設保持著多項世界記錄，中國躋身于世界橋梁建設強國行列。

　　China boasts a long history in bridge construction.With wood and stone as the major buildingmaterials, Chinese ancient bridges vary in forms andare highly distinct.Constructed in the Sui Dynasty, Anji Bridge, which is located in Zhao County, HebeiProvince, is the oldest existing bridge in China.Anji Bridge, also named Zhaozhou Bridge, is akey national protected cultural relic measuring a length of 50.82 meters and a width of 9meters.In the late years of the Qing Dynasty, Huanghe Iron Bridge in Lanzhou was completed,symbolizing that China's bridge construction stepped into an era of adopting steel andconcrete as the main materials for bridges.Now, bearing many world records, China standsamong world giants in bridge construction.

　　1.第二句中的“以……為主要建筑材料”可處理為狀語，用介詞短語with……as the major building materials表達，而“中國古代橋梁”宜譯為“形式多樣，極富特色”的主語，謂語部分“形式多樣，極富特色”可處理為并列內容，用and連接，表達為vary in forms and are highly distinct.

　　2.第三句“中國現(xiàn)存最古老的橋梁…位于河北省趙縣”的定語較多，可以拆譯成兩句。首先譯出主要結構Anji Bridge is the bridge，“現(xiàn)存最古老的”有兩個形容詞，英語中的比較級或最高級形容詞通常在其他形容詞之前，故譯為oldest existing.“隋代建造的”可處理為過去分詞短語constructed in the Sui Dynasty 或which引導的定語從句。

　　3.第四句的主干是“安濟橋為國家重點保護的文物”，故把“又名趙州橋”處理為插入語also named…;將“橋長50.82米，橋寬9米”處理為伴隨狀態(tài)的狀語，用分詞短語measuring a length of…and a width of…譯出。

　　4.倒數(shù)第二句中的“蘭州黃河鐵橋”與“建成”之間是被動關系，翻澤時需把“建成”譯為被動式wascompleted.“標志著中國…”是結果，故可處理為狀語，用現(xiàn)在分詞短語symbolizing that…表達。定語“以鋼鐵和混凝土為主要材料的”較長，可處理為后置定語，用現(xiàn)在分詞短語adopting…as the main materials 表達，也可用介詞短語with…as the main materials翻譯。

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