台湾籍旅美老师今天交给我们的句子是：

For example, a fear reaction leads to a response of, say, running away from a predator that in turn, ensures your survival.
举例来说，对于恐惧的反应会导致一些行为，例如让你远离掠食者等。反过来说，就是确保自己能生存。