He has____disability which prevents him from walking,but he has ____gift for art.

He has____disability which prevents him from walking,but he has ____gift for art.
A.a;a B.the;the C.不填；a D.a;the
更重要的一个问题
冠词 a/an;the;或是不填 分别在什么时候用 请辨析一下冠词 a/an ;the; 不填 分别什么时候选择