Essentially, a theory is an abstract symbolic representation of what is conceived to be reality
从本质上讲，理论是对认识了的现实的抽象概括和符号表达
Long before children are able to speak or understand a language ,they communicate through facial expressions and by making noises
在小孩学会语言表达之前，他们只能靠面部表情或者制造声响来进行自我表达。
Thanks to modern irrigation crops now grow abundantly in areas where once nothing but cacti and sagebrush could live
感谢现代农业灌溉水平的进步，使大量的农作物可以种植在以前只有仙人掌和山艾树才能生长的地方。
