题型分类：事实信息题

原文定位：定位词：difficult to define。利用定位词定位到第一段第四句，对应其中的“One of the problems in providing a clear definition of play …”，第四句完整意思是“定义玩耍的难题之一是，玩耍过程中包含着一些与其它情况下相似的行为，例如统治，捕食，竞争和搏斗。”

选项分析：

B选项说“Play behavior often looks like nonplay behavior.”，对应第一段第四句，提到“involves the same behaviors that take place in other circumstances – dominance, predation, competition, and real fighting”。

A选项说“Play must be defined with concepts, not examples.”，第一段第一句说“Play is easier to define with examples than with concepts.”，因此与原文描述不符。

C选项说“Play often occurs in the presence of animals that are not playing.”，文中无此信息，无中生有。

D选项说“Play occurs independently of an animal’s intentions.”， 而第一段最后一句说“Thus, whether play occurs or not depends on the intention of the animal, and intentions are not always clear from behavior alone.”意思是“因此，判断其是否玩耍，要根据动物的目的来确认，而常常通过行为本身很难分析其目的。”因此选项与原文描述不符。