下列遗址中,反映原始农耕文化的是
①山顶洞人遗址②半坡遗址③河姆渡遗址④北京人遗址[ ]
A.①②
B.③④
C.②③
D.①④
答案:C
It was his mother came in to prepare his lessons. [ ]
A. not until; did the boy begin
B. until; that the boy began
C. until; did the boy begin
D. not until; that the boy began
锚喷支护施工方法又称新奥法。