能促进气血循环、改善组织营养、消除炎性水肿的是()。能提高肌肉组织的兴奋性,对横纹肌有良好的刺激收缩作用的是()。
A.疏波
B.密波
C.疏密波
D.断续波
E.锯齿波
参考答案:C,D
一个队列的初始状态为空。现将元素A,B,C,D,E,F,5,4,3,2,1依次入队,然后再依次退队,则元素退队的顺序为______。
Passengers on board aren't allowed _____ calls during take-off.
A.making or receiving
B.to make or receive
C.to have made or received
D.having made or received