author n．作客，创造者
例句：After the play they called for the author to show himself.
演完戏之后，他们要求作者出来和大家见面。

authentic adj. 可信的
例句：Tom has got an authentic letter by Shakespeare.
汤姆弄到了一封莎士比亚的亲笔信。

authoritative adj. 权威的，有权威
例句：The commander spoke rapidly and in an authoritative manner.
那个将军讲话讲得很快，而且用的是命令式的口气。

authorize v．批准
例句：I have authorized him to act for me while I am away.
我已经委托他当我不在的时候代我处理。

authority n．权威，威信，权威人士
例句：His parents think that the contemporary young people have no respect for auth．
他的父母认为现在的年轻人不尊重权。