In the 1960s,runners were mostly athletes and healthy strong people.
在20世纪60年代,参加赛跑的大多都是运动员和体魄健壮的人.most填这就不对吗？most形容词,而mostly副词,修饰be动词were most一般这样用In the 1960s, most of the runners were athletes and healthy strong people.或者直接most runners were athletes and healthy strong people这样就没错