A. are B. will be going C. must D. were
昨日习题答案： The snow（ A. kept on ） for several days and everything was in white. 句意：雪连续下了几天，万物都变成了白色的。 keep out 把...关在外面; 阻止入内; 不参加; 不进去; keep off 避开; 不(让)接近; 防止; (雨雪)没有下 keep back 退缩; 隐瞒; 留/扣下; 阻止 keep on 单独用，表继续（处在某种状态）。