1.Essentially,a theroy is an abstract,symbolic representation of what is conceived to be reality.
本质上讲，一种理论是对它所认为的事实的一种抽象和符号化的表达。
2.Long before children are able to speak or understand a language,they commuicate through
facial expressions and by making noises.
早在儿童能够说话或听懂一种语言之前，他们通过面部表情和发出声响来与人沟通。
3.Thanks to modern irrigation,corps now grow abundantly in areas where once nothing but cacti and sagabrush could live.
多亏了现代灌溉技术，农作物现在也能在曾经只有仙人掌和山艾树生长的地方茂盛地成长。
