70.历代文学作品中的英雄本色虽各有千秋，但其昭世功力却是恒古不变的。

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.

69.雪对农民是一种帮助，因为它保持地层土壤的温度，使种子不致冻死。

69. Snow aids farmers by keeping heart in the lower ground levels, thereby saving the seeds from freezing.

68.主要目的在于丰富和优质的农艺学利用了其他科学的知识。

68. The science of horticulture, in which the primary concerns are maximum yield and superior quality, utilizes inFORMation derived from other sciences.

67.科学家不知道恐龙为何绝种了，但是一些理论推断是地理，气候和海平面的变化造成的。

67. Scientists do not know why dinosaurs became extinct, but some theories postulate that changers in geography, climate, and sea levels were responsible.

66.鲇鱼不仅可以离开水存活，还可以在岸上短距离移动。

66. Not only can walking fish live out of water, but they can also travel short distances over land.