His brother always wears---uniform to school.A.a B.anC./D.th

一般不加冠词,uniform可以表示一类东西,像是fruit,vegetable,
如果是特指某件校服,用wear the uniform,但前面要提到过这件校服
没有wear a/an uniform的用法
再问： 那a uniform呢？什么时候用？给个例子呗
再答： A: what did Tom wear to the party? （Tom 穿什么去派对？） B: He worn a uniform, which he borrowed from his borther. （他穿了他从他哥那里借来的一件校服）