当干冰气化时，下列所述中发生变化的是 A.分子间距离 B.、范德华力 C.分子内共价键
在△ABC中，A(1，－1)，B(1，1)，C(3，－1)，求三边所在直线的倾斜角和斜率．
Odiand remembers like it was yesterday working in an expensive French restaurant in Denver．The ice cream he was serving fell onto the white dress of a rich and important woman． ．Thirty years hav
（附加题）甲乙两年在公路上沿同一方向做直线运动，它们的v-t图象如图所示。两图象在t=t1时相交于P点，P在横轴上的投影为Q，△OPQ的面积为S。在t=0时
一列简谐横波沿x轴正方向传播， t时刻与（t＋0.6）时刻的波形图正好重合，如图所示。则下列说法中正确的是（ ）（A）质点振动周期可能为1.2s
The annual marathon in my town usually occurred during a heat wave. My job was to 1 behind the runners in an ambulance 2 any of them ended medical attention. The driver and I were in an air - condit
把函数的图象上所有点的横坐标缩短到原来的倍（纵坐标不变），然后把图象向左平移个单位，则所得到图象对应的函数解析式为
