螺距（）导程。
A.等于
B.不等于
C.无法确定
D.小于
参考答案：C
25. John, _______ money is no problem, still leads a simple life.
A．for whose
B．of whose
C．of whom
D．for whom
冷凝水收集井应每隔（）设置一个。
A.15～50m
B.50～80m
C.60～150m
D.200～300m
