The chances of discovering life on Neptune are about a million .A. at oneB. for oneC. to o

问题补充：

The chances of discovering life on Neptune are about a million .

A. at one

B. for one

C. to one

D. against one

答案：

A. at one

B. for one

(答案→)C. to one

D. against one

解析：a million to one百万分之一，意为“几乎没有什么可能”。