在计算机中有许多资源一次只能允许一个进程使用，如果多个进程同时使用这些资源，则有可能造成系统的混乱，这些资源被称为（）。
参考答案：临界资源
In the past few years, so many areas throughout the world have been hit by such destructive earthquakes, snowstorms and tsunamis ________ we have never experienced before, ________ makes us worried a lot about nature disasters.
A．that; that
B．as; which
C．which; it
D．when; as
精子与卵细胞结合成受精卵的部位和胚泡着床的部位依次是 [ ]
A．卵巢、输卵管
B． * * 、子宫
C．卵巢、子宫
D．输卵管、子宫
