Paragraph Three When infants 18 months old see an unrelated adult whose hands are full and who needs assistance opening a door or picking up a dropped clothespin, they will immediately help. The helping behavior seems to be innate because it appears so early and before many parents start teaching children the rules of polite behavior. 38. Human beings may be b____ with the urge to help.
【正确答案】：birth
【题目解析】：题干主要描述了人类天生就有帮助的冲动，题干中提到的innate就是先天的意思，横线上的词与be和with组成使用应该有“先天的”意思，而be birth with ……就是先天的意思。
