露天深孔爆破的孔径主要取决于钻机类型、台阶高度和岩石性质。
参考答案：对
比的前后项都可以是任何一个自然数。[ ]
I will remember such a beautiful village forever _________ I spent my childhood there with my parents.
A．that
B．where
C．in which
D．because
