【单选题】
Change, or the ability to (31) oneself to a changing environment is essential (32) evolution. The farmer whose land is required for housing or industry must adapt himself: he can transfer to another place and the problems (33) to it; he can change his occupation, perhaps (34) a period of training; or he can starve to death. A nation which can’t adapt its trade or defense requirements to (35) world conditions faces an economic and military disaster. Nothing is fixed and permanently stable. (36) must be movement forward, which is progress of a sort, and movement backward, which is decay and deterioration.
In a changing world, traction can be a force for good or for evil. (37) long as it offers a guide, it helps the ignorant and the uninformed to take a step (38) and, thereby adapt themselves to (39) circumstances. But if we make an idol of tradition, it ceases to be a guide. It becomes an obstacle (40) on the path of course. Man is to accept the help which tradition can give but to be well aware of its limitations in a changing world.