【单选题】设 ,若“方程 满足 ,且方程至少有一根 ”,就称该方程为“漂亮方程”。则“漂亮方程”的个数为
【单选题】设集合 ,如果方程 ( )至少有一个根 ,就称该方程为合格方程,则合格方程的个数为( )
【简答题】若线性方程组设方程有无穷多个解,则a=________.设方程 有无穷多个解,则a=________.
【单选题】When the children leave home, the writer thinks that ______.
A.
there will be compensations
D.
there will be nothing to do
【单选题】下述正弦交流电路中的电感描述错误的是( )
B.
正弦交流电路中电容的无功功率与电压平方成正比
C.
正弦交流电路中电容的无功功率与电流平方成正比
D.
正弦交流电路中电容的无功功率等于电压有效值除以电流有效值
【简答题】根据塑料中树脂的分子结构及特性可以分为 和 塑料两大类。
【判断题】当地势高低差超过20cm时,先用手动进行粗平。按标高图上的方位,从高处向下刮土。
【简答题】Psychologists tell us that there are four basic stages that human beings pass through when they enter and live in a new culture.This process begins with the “honeymoon stage”.This is the period of tim...
【单选题】The writer says he turns into a 'gas'______.
B.
when being with the guests
C.
when wearing the old clothes
D.
when talking with his guests