[9급 지방직 영어 2016년 20번]

One well-known difficulty in finding new things has been termed the 'oasis trap' by the cognitive psychologist David Perkins. Knowledge becomes centered in an 'oasis' of rich findings and it is just too risky and expensive to leave that still productive and well-watered zone. So people stick to _________________________. This is what happened to a certain extent in China over many centuries. The huge physical distances between centers of knowledge in China and the fact that the distant centers turned out to be little different from one another discouraged exploration.