NaCl的晶胞如图，每个NaCl晶胞中含有的Na+离子和Cl-离子的数目分别是
A．14,13
B．1,1
C．4,4
D．6,6
答案：C
It’s exactly ______ we do ______ has changed the world.
A．which; that
B．how; that
C．how; what
D．what; that
汽车电磁式轮速传感器齿圈有哪些失效形式？
