As is known to all one of the many benefits of adventure travel is teaching children how

问题补充：

As is known to all, one of the many benefits of adventure travel is teaching children how to cope with unexpected.

A. the; /

B. /; an

C. the; the

D. /; the

答案：

A. the; /

B. /; an

C. the; the

(答案→)D. /; the

解析：D考查冠词。此处travel为不可数名词，其前用零冠词；第二空用定冠词the，与其后的过去分词unexpected连用，表示“意外的事情”。