When he realized the police had spotted him, the man（）the exit as quickly as possible.

单项选择题The survival（）of some wild animals is not very high as they are ruthlessly hunted for their skins

A．standard
B．scale
C．ratio
D．rate

单项选择题John Locke, the well-known 18th century English thinker, emphasized experience as the （）condition for expansion of human knowledge.

A. incompatible
B. incredible
C. indefinite
D. indispensable