people have always been curious how living things on the earth exactly began.A. inB. atC.

问题补充：

people have always been curious how living things on the earth exactly began.

A. in

B. at

C. of

D. about

答案：

A. in

B. at

C. of

(答案→)D. about

解析：介词辨析。句意：人们总是对地球上的生物如何确切的出现的很好奇。选D，关于，表示好奇的对象。