【单选题】2017 年 4 月 14 日,上海轨道交通 9 号线早高峰中断运营,是由于( )设备故障。
【简答题】设集合M={y|y=-x 2 +1},N={y|y=x+1},M∩N=______.
【单选题】There can be no question about the dangers of heroin use. What may start out innocently enough as a desire to experience a new kind of high may progress with extreme rapidity to an almost continuous t...
A.
won't lead to addiction
B.
will rapidly make the person have a terrible dream
D.
may immediately endanger the existence of the person who tries
【简答题】设集合M={x| y= x-2 },N={y|y=x 2 ,x∈R},则M∩N等于 ______
【简答题】设U={(x,y)|x∈R,y∈R},A={(x,y)|2x-y+m>0},B={(x,y)|x+y-n≤0},如果P(2,3)∈A∩(C U B),那么m,n的取值范围分别是______.
【单选题】设集合M与集合N都是点集{(x,y)|x∈R,y∈R},映射f:M→N把M中元素(x,y)映射成N中元素(x+y,x-y),则象(2,1)的原象为 [ ]
【简答题】接上,格劳孔提出三个问题后,阿得曼托斯列举了许多现实生活中的现象,这些现象使人们怀疑,不相信正义。他说了哪些现象?