客货共线铁路线间距,160km/h<v≤200km/h区间双线线间最小距离为()。
A.4200mm
B.4400mm
C.5000mm
D.4000mm
参考答案:B
It’s the _______ that caused the big forest fire. A young man dropped it carelessly at picnic.
A.cigarette end
B.electric light
C.lightning
D.thunder
皮肤针法和皮内针法运用的理论依据是什么?为什么?