1.Scientists do not know why dinosaurs bacame extinct, but some theories postulate than changers in geography,climate,and sea levels were responsible.
科学家们不知道恐龙为什么会灭绝,但有些理论推测是由地理,气候以及海平面的变化所导致的.
2. The science of horticulture, in which the primary concerns are maximum yield and superior quality,utilizes information derived from other sciences.
最关心最大收益和上乘质量的园艺科学,可以利用来自其它科学的信息。
3.Snow aids farmers by keeping heat in the lowerground levels, thereby saving the seeds from freezing.
雪可以帮助农民保持浅层地面的热量，从而使种子免遭冰冻。
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