句中由as或such as, for example等引导学的短语或句子为举例句，常考“修辞目的问题"和“细节性问题"。
(1)An ecologist who studies a pond today may well find it relatively unchanged in a year' S time. Individual fish may be replaced, but the number of fish will tend to be the same from one year to the next. We can say that the properties of an ecosystem are more stable than the individual organisms that compose the ecosystem.
According to paragraph 2, which of the following principles of ecosystems can be
learned by studying a pond?
A. Ecosystem properties change more slowly than individuals in the system.
B. The stability of an ecosystem tends to change as individuals are replaced.
C. Individual organisms are stable from one year to the next.
D. A change in the members of an organism does not affect an ecosystem' S properties
解析：通过“池塘”，我们可以定位到红色部分这句话。然后鱼可以会被替代，但是鱼的数量可能一直以来都是一样的，“We can say”后面的意思跟前面这句话的意思是一样的。这道题的答案是D。