Human beings have distinguished themselves from other animals, and in doing so ensured their survival, by the ability to observe and understand their environment and then either to adapt to that environment or to control and adapt it to their own needs.
These expenses , however, usually involve the rent of a small office , expenses for stationary, and possibly , the salary of a secretary.
He must assume that you have lived in the tropics , have never seen a coat worn or put on, and that he is to tell you verbally how to do it.
要點分析和參考譯文
要點：此句為一個多層次的並列結構，by 以前的部分為句子的主體部分，由and連線的兩個並列的`分句組成。第二個分句的主語和一部分謂語省略了以避免重複。In doing so可以理解為in the process of distinguished themselves from other animals.第二個分局的完整句子應為and in doing so （they have） ensured their 所引導的短語裡ability帶了多個動詞不定式做修飾，這些不定式又存在著一個並列的結構，to observe and （to） understand與eitheror引導的to adapt to，to control and （to） adapt it得並列，and連線。
參考譯文：人類已把自己和其他動物區別開了。人類具有觀察和了解周圍環境的能力，能適應環境，控制環境和根據自己的需要改造環境。人類就是這樣生存了下來。
