在下列分子结构中,原子的最外层电子不能满足8电子稳定结构的是[ ]
A.N2
B.PCl3
C.HCl
D.CO2
答案:C
Did you like the latest movie? No, it was so bad it made me _______.[ ]
A. happy
B. pleased
C. upset
D. crying
如图所示是做直线运动的甲、乙两物体的x-t图象,下列说法中正确的是()
A.甲、乙两个物体启动的时刻相同
B.当t=t2s时,两物体相遇
C.当t=t2s时,两物体相距最远
D.当t=t3s时,两物体相距最近