什么是级配碎石路面?
参考答案:
用粒经大小不同的粗细砾(碎)石各占一定比例的混合料,当其颗粒组成符合密实级配要求成级配砾(碎)石,这二者做面层时叫级配砾(碎)石路面。
我国的华山是断块山。
—Dad, when will you be free? You agreed to go to the seaside with me four days ago.
—I'm sorry, Jack. But I think I will have a _______ holiday soon. [ ]
A. four-days
B. four-day
C. four days
D. four day