降尘的具体措施有煤层注水、()、水封爆破水炮泥、()、通风除尘和()。
参考答案:采空区灌水;喷雾洒水;清扫落尘
Though the road covered with snow was very smooth, the old man smilingly ____ to be helped by others across the road.
A.refused
B.declined
C.accepted
D.promised
腹部膨隆可由哪种原因引起()①巨大腹膜后肿瘤②过度肥胖③腹水④巨大卵巢肿瘤
A.①③
B.①③④
C.①②③
D.以上各项均是