造成黄河下游河床增高,形成“悬河”的主要原因是[ ]
A.历史上曾发生严重泥石流
B.黄土高原植被破坏,土壤冲刷沉淀而成
C.黄河流域食物链被破坏
D.黄河下游环境受污染
答案:B
据《素问•生气通天论》,“清静则肉腠闭拒”的“清静”是指()
A、四时气候清静正常
B、人体阳气清静正常
C、人体阴阳平衡协调
D、人体精神清静不乱
E、天气清静正常
Some children were skating on the ice happily. Suddenly one of them ____ the water and the other children
felt ____. [ ]
A. falls into; mad
B. fell into; frightened
C. fall into; mad
D. felt into; frightened