I wasthe edge of the canyon. A river was the bottom of the canyon.A. at；onB. on；inC. on；at

问题补充：

I wasthe edge of the canyon. A river was the bottom of the canyon.

A. at；on

B. on；in

C. on；at

D. in；at

答案：

A. at；on

B. on；in

(答案→)C. on；at

D. in；at

解析：句意:我在峡谷的边缘，一条河就在峡谷的底下。本题考查介词，第一个空是短语on the edge of 在……的边缘；第二个空是at the bottom of 在……的底下。故应选C。