下列化学用语表示正确的是( )
A:两个氮原子:N2
B:熟石灰的化学式:Ca(OH)2
C:正二价的镁元素:Mg+2
D:铝与盐酸的反应:Al+2HCl=AlCl2+H2↑
注:反应Ⅱ的离子方程式为Cu2++CuS+4Cl﹣=2CuCl2﹣+S↓
请回答下列问题:
Jim records his physical training every time so that he can________it and think about how he should improve it the next day.
________ people visit the Great Wall every day.