Humans, like other animals>interact through _____ behavior by means of signs or symbols used conventionally. (communicate)
【正确答案】：communicative
【题目解析】：译文：人类像其他动物一样,通过习惯上常使用的符号或标志性的交际行为来沟通。本句话through介词短语不完整,缺少名词的形容词作修饰语。communicate的形容词为communicative。答案为communicative。
