单项选择题
A.鱼是最显而易见的污染受害者，但它只不过是从微生物到人类这一长链中的一环罢了。 B.在从微生物到人类这一长链中，鱼是污染的唯一受害者，而且是最容易看见的。 C.污染影响着所有的生物界，但鱼是最显而易见的受害者。 D.最明显的污染受害者们构成了从微生物到人类的长链，而鱼则仅仅是其中的一环。
A．a slip of paper with which you are permitted to enter a theater B．a notice issued to someone who has violated a traffic regulation C．a slip of paper with which you can see a film D．a notice that shows your right to do something
A．The stranger on a black horse is a seal doctor. B．We know that this is not a true story. C．The old grey seal puts the knife beside the bed. D．The seal hunter’s name is Donald A. Mackenzie.