2019年GRE考试填空练习试题及答案解析20
　　58、 Once a duckling has identified a parent, the instinctive bond becomes a powerful _________ for additional learning　since, by _________ the parent, the duckling can acquire further information that is not genetically transmitted.
　　(A) impulse...surpassing
　　(B) referent...recognizing
　　(C) force...acknowledging
　　(D) inspiration...emulating
　　(E) channel...mimicking
　　分析：空格 1 填入一个名词，表示"本能的纽带(instinctive bound)"和"进一步学习(additional learning)"之间的关系;空格 2 填入一个现在分词，表示小鸭子对它 ...