D
Students 是主语
brave enough to take this adventure course 是定语,修饰主语。
D
adj. + enough to do sth.是固定搭配 有什么能力做某事的意思
而本句的主语应该是人studengts,所以选D
choose D
该句的主语是一个主语从句,全从句是 Students who are brave
enough to take this adventure course 在这个从句里又有一个定语从句students 为先行词,who are brave enough to take this
adventure course 是从句.接下来是定语从句的省略,从句的主语who
和先行词students 意义相同,则who可省略,同时are省略.