65. Although mockingbirds superbly mimic the songs and calls of many birds, they can nonetheless be quickly identified as mockingbirds by certain aural clues.
    盡管模仿鳥學很多種鳥的鳴叫聲惟妙惟肖，但人類還是能夠依其聲音上的線索很快識別它們。
　　
66. Not only can walking fish live out of water, but they can also travel short distances over land.
    鲇魚不僅可以離開水存活，還可以在岸上短距離移動。
　　
67. Scientists do not know why dinosaurs became extinct, but some theories postulate that changers in geography, climate, and sea levels were responsible.
    科學家不知道恐龍為何絕種了，但是一些理論推斷是地理，氣候和海平面的變化造成的。
　　
68. The science of horticulture, in which the primary concerns are maximum yield and superior quality, utilizes inFORMation derived from other sciences.
    主要目的在于豐富和優(yōu)質(zhì)的農(nóng)藝學利用了其他科學的知識。
　　
69. Snow aids farmers by keeping heart in the lower ground levels, thereby saving the seeds from freezing.
    雪對農(nóng)民是一種幫助，因為它保持地層土壤的溫度，使種子不致凍死。
　　
70. Even though the precise qualities of hero in literary words may vary over time, the basic exemplary function of the hero seems to remain constant.
    歷代文學作品中的英雄本色雖各有千秋，但其昭世功力卻是恒古不變的。
　　
71. People in prehistoric times created paints by grinding materials such as plants and clay into power and then adding water.
    史前的人們制造顏料是將植物和泥土等原料磨成粉末，然后加水。
　　
72. Often very annoying weeds, goldenrods crowd out less hardy plants and act as hosts to many insect pests.
    花通常令人生厭，它擠走不那么頑強的植物，并找來很多害蟲。