III. ReadingComprehension (40points)
From the earliest of times, sailorshavefoundways to navigatetheirships on the seas and oceans of the worl (D)The earliestsailorsnavigated by simplyfollowing the coastline. Asidefrombeing a ratherslowmethod of navigating, thismethod was alsoratherdangerous and limite (D)It was dangerous in thatwatersclose to the shorelinecould be shallowenough to strand a ship or the waterscould be full of rockyprotrusionscapable of sendingships to theirgraves. Whenseafarersbegansailing out of sight of landmorethan 4000 years ago, theyused the stars to determinetheirdirection. Theycalculated the distancetraveledfromtheirspeed and sailingtime, and theydrewroughcharts and maps to findtheir way and to exchangeinformationaboutnavigationalrouteswithothers. It had alsobeenknown as early as 300 (B) (C) that a sundialcasts a longershadow as it is movedfarthernorth of the equator, and thisinformation was used by sailorsfromthattime to get an idea of how far north of the equator a ship was. All of thesemethodsprovidedonlyveryrudimentarymeans of navigation.
It was not untilmorethan 3000 yearsaftersailors set out on the seasthat the compass was develope (D)The premise of a compass is that the magnetizedneedle of a compass, when it is balanced on a centralpivot or left to float on liquid, willalwaysturn to point in the direction of magneticnorth. Navigators on Chineseshipswere the firstones who wereknown to use compasses to determine the directiontheirshipswereheading, as early as 1100.
Numerousinventionswerecreated to determine a ship's latitude. With the invention of the astrolabe in the fourteenthcentury, sailorswereable to measure the Sun's heightwithbetteraccuracythanwith a sundial, and theywereable to use the informationprovided by the astrolabe to determine how far north of the equatortheywere. An astrolabe was a metalcirclewith a sightingrulethatrotated in the circle; the rulecould be alignedwith the Sun, and measurements on the ringindicated the Sun’s height. Otherdevicesfollowedthatwerebetterable to determine the Sun’s
height and thusprovide an idea of the ship’s latitude. The backstaff, invented in 1595, and the sextant, invented in 1757, weredevicesthateachimproved a navigator's ability to determinelatitude. The backstaff was a devicethatrequired the navigator to faceawayfrom the Sun and make a calculation of the shadow in relation to the horizon. The sextant was a measuringdevicethatrequired the navigator to lookinto an eyepiece and calculate the Sun’s positionrelative to the horizon and thencheckprintedtables to convertthisinformationintolatitude.
The missingpiece in the navigationalpuzzle was the ability to calculatelongitude or how far east or west a ship had travele (D)The need for a device to calculatelongitude was so important to navigatorsthat the EnglishParliamentoffered a reward of 20,000 pounds (an extraordinarilylarge sum at the time, perhaps $10 million in today's currency) to anyone who couldinvent a method for calculatinglongitude. In 1759, EnglishclockmakerJohnHarrisonbuilt a chronometerthat was accurateenough for navigation. The premise of the device was that the Sun rises two secondslatereach dav for eachkilometertraveled in a westerlydirection, so the accuratelymeasuredchange in time was an accurate wav to calculatelongitude. Harrison was easilyable to convinceParliamentthat the reward was warrante (D)
【題組】34. Which of the followingnavigationaldevices can be used to resolvedirectionalissueswhennavigating?
(A) Sundial (B) Astrolabe (C) Coastline (D)All of the above
【題組】35. It is NOT stated in the passagethat the astrolabe (A) was used to determinedistancefrom the equator. .
(B) was similar in shape to a sundial.
(C) had movingparts.
(D)was a circular-shapeddevice.