The function of an air conditioning system is to provide and maintain an artificial environment within a building enclosure . 空气调节系统的作用是建立和维持建筑物内的人工气候。
our main concern will be with single crystals deliberately prepared and of a size greater than about 1 m. 我们研究的主要是人工制造的体积大于1m左右的单晶。
This revolution was primarily a dry farming operation with springs and shallow hand-dug wells supplying domestic needs . 这次革命主要是旱田耕作而以泉水和人工开挖浅井提供生活用水。
The agency will require the right to spread surface water, including reclaimed wastewater for ground water recharge . 为了地下水人工补给，该机构需有引渗地表水（包括已回收的废水）之权。
There is a great contrast between nutrient cycles in natural vegetation and the nutrients involved in growing an arable crop . 天然生长的植物与人工栽培的作物在营养循环方面有很大的差异。
Forest ecologists have been more concerned than agronomists with the inner mechanisms of natural and artificial ecosystems . 森林生态学家比农学家更关心天然生态系统和人工生态系统的内部机制。
The actual plan of a city is never a mere artifact, it is always quite as much a product of nature as of design . 一项现实的城市规划绝不仅仅是一个人工物，它往往既是设计的产物又是自然的结果。
We could watch some mad men, on clement days, sauntering among the trim gravel walks and pleasantly planted lawns . 在天气暖和的日子里，我们可以看到一些疯子在整齐的碎石小径和美丽的人工草地间闲逛。
Cholecalciferol is produced by irradiation of 7-dehydrocholesterol with ultraviolet light either from the sun or from an artificial source . 胆钙化醇是7脱氢胆固醇经日光或人工来源的紫外线照射而产生的。
It may offer mountain scenery, the combination of sun and sea, or features that are entirely manmade, like disneyland in california . 那里有湖光山色，阳光大大海或者完全由人工塑造的景致，如加利福尼亚州的迪斯尼乐园等。
