a study by Allan Lucks ,director of Big Brothers Big Sisters ,found volunteers had better health than non-volunteers .A
问题描述：
a study by Allan Lucks ,director of Big Brothers Big Sisters ,found volunteers had better health than non-volunteers .A was led B led C leading D was leading 该选择哪个?
答
选B,题中已有动词found,不能出现第二个动词,只能用非谓语动词,而lead与主语是被动关系,所以选B