51. Using many symbols makes it possible to put a large amount of inFORMation on a single map.

51.使用多種多樣的符號(hào)可以在一張地圖里放進(jìn)大量的信息。

52. Anarchism is a term describing a cluster of doctrines and attitudes whose principal uniting feature is the belief that government is both harmful and unnecessary.

52.無(wú)政府主義這個(gè)詞描述的是一堆理論和態(tài)度，它們的主要共同點(diǎn)在于相信政府是有害的，沒(méi)有必要的。

53. Probably no man had more effect on the daily lives of most people in the Untied States than did Henry Ford a pioneer in automobile production.

53.恐怕沒(méi)有誰(shuí)對(duì)大多數(shù)美國(guó)人的日常生活影響能超過(guò)汽車(chē)生產(chǎn)的先驅(qū)亨利.福特。

54. The use of well-chosen nonsense words makes possible the testing of many basic hypotheses in the field of language learning.

54.使用精心挑選的無(wú)意義詞匯，可以檢驗(yàn)語(yǔ)言學(xué)科里許多基本的假定。

55. The history of painting is a fascinating chain of events that probably began with the very first pictures ever made.

55.優(yōu)化歷史是由一連串的迷人事件組成，其源頭大概可以上溯到最早的圖畫(huà)。

56. Perfectly matched pearls, strung into a necklace, bring a far higher price than the same pearls told individually.

56.相互般配的珍珠，串成一條項(xiàng)鏈，就能賣(mài)到比單獨(dú)售出好得多的價(jià)錢(qián)。

57. During the eighteenth century, Little Turtle was chief of the Miami tribe whose territory became what is now Indiana and Ohio.

57.十八世紀(jì)時(shí)，“小烏龜”是邁阿密部落的酋長(zhǎng)，該部落的地盤(pán)就是今天的印第安那州和俄亥俄州。

58. Among almost seven hundred species of bamboo, some are fully grown at less than a foot high, while others can grow three feet in twenty-four hours.

58.在竹子的近七百個(gè)品種中，有的全長(zhǎng)成還不到一英尺，有的卻能在二十四小時(shí)內(nèi)長(zhǎng)出三英尺。

59. Before staring on a sea voyage, prudent navigators learn the sea charts, study the sailing directions, and memorize lighthouse locations to prepare themselves for any conditions they might encounter.

59.謹(jǐn)慎的航海員在出航前，會(huì)研究航向，記錄的燈塔的位置，以便對(duì)各種可能出現(xiàn)的情況做到有備無(wú)患。

60. Of all the economically important plants, palms have been the least studied.

60.在所有的經(jīng)濟(jì)作物中，棕櫚樹(shù)得到的研究最少。