A:﹣5,5
B:﹣1,9
C:−12,2
D:12,3
They finished their meal in silence.
A: Do you miss Mr Chen? B: Yes. I do.______ have you ever heard of him since he left?
“研究匀变速直线运动”的实验中,使用电磁式打点计时器(所用交流电的频率为50Hz),得到如图所示的纸带.图中的点为计数点,相邻两计数点间还有四个点未画出来,下列表述正确的是( )