hiking is_great fun ,you can get close to _and take exercise at the same time .

问题描述:

hiking is_great fun ,you can get close to _and take exercise at the same time .
A,a;the B,a;/ c,/;the D,/;/

D 后面一个是空 后面少了nature吧,nature前无冠词
前面fun是不可数名词,不能加a