Pumas are large, cat-like animals which are found in America. When report came into London Zoo that a wild puma had been spotted forty-five miles south of London, they were not taken seriously.
- that a wild puma had been spotted forty-five miles south of London是同位语从句，做reports的同位语，进一步说明报告内容
- take sth. seriously 认真对待某事
However, as the evidence began to accumulate, expert from the zoo obliged to investigation, for the descriptions given by people who claimed to have seen the puma were extraordinarily similar.
美洲豹是一种大型的猫科动物，通常生活在美洲大陆。当伦敦动物园接到报告说，在伦敦以南45公里处发现美洲豹时，这些报告并没有收到重视。然而，随着目击报告的增加，动物园的专家认为有必要进行一番调查，因为那些声称见到了美洲豹的人所描述的情况是出奇的类似。
- as 引导的方式状语、同级比较状语、原因状语和插入语
- the description given by people 中 given by people 为过去分子短语作定语，修饰description。description常与动词give或make搭配使用，在描述人或物前使用介词of：give/make a description of sth./sb.
- who claimed to have seen the puma 中 who 引导定语从句，修饰其前的people。to have seen 为动词不定式的完成时结构，表示动词不定式的动作发生的在谓语动词claimed之前。
- because与for的区别：because表直接原因，语气更强烈，回答由why引出的问句；for引导的是并列分句，对前面的分句加以解释，起补充说明推断的理由，语气较弱，只能位于后半句。
例如：Bill knew that he would be able to reach the south pole, for there were no more mountain in sight.- since, becuase 与 as 的区别：because语气最强，since次之，as最弱。because强调原因，而since和as表示原因为既成事实，强调引起的后果。
- Since your children have grown up, you needn't work hard any longer.
- oblige:迫使，不得不。强迫性较弱，但必要性很强，常用于被动式。
The hunt for the puma began in a small village where a woman picking blackberries saw 'a large cat' only five yards away from her. It immediately ran away when she saw it, and experts confirmed that a puma will not attack a human being unless it is cornered.
- 关系副词where引导定语从句，修饰先行词a small village。
- 第二句是一个含有宾语从句的复合句，that引导从句做confirm的宾语，而该宾语从句又包含一个unless的条件状语从句。注意：在unless引导的从句中，要使用现在时形式！
The search proved difficult, for the puma was often observed at one place in the morning and at another place twenty miles away in the evening. Whenever it went, it left behind it a trail of dead deer and small animals like rabbits. Paw prints were seen in a number of places and puma fur was found clinging to bushes.
