钻孔取芯钻进，岩芯采取率：砂和砂砾层大于（）。
A.50％
B.40％
C.70％
D.30％
参考答案：D
—I’m sorry for being late, Miss Green. —___________.
A．That's right
B．You are welcome
C．It doesn't matter
D．You should be sorry
上颌纵合曲线前段
