选项
实验目的
试剂或方法
A
鉴别FeCl3、NaCl、NaOH、MgCl2四种溶液
不另加试剂
B
鉴别CaCO3、NaOH、NaCl、NH4NO3四种固体
水
C
除去MgCl2溶液中少量的CuCl2
加入过量铁粉、充分反应、过滤
D
除去N2中的少量O2
将气体缓缓通过灼热的铜网
A：A
B：B
C：C
D：D
已知抛物线C：y2=2px（p＞0）的焦点为F，直线y=4与y轴的交点为P，与抛物线C的交点为Q，且|QF|=2|PQ|，过F的直线l与抛物线C相交于A，B两点．
阅读理解
Name: Kelsey
Age: 22
I can sing and dance. I can play the violin and the piano, but I can't play the guitar.
Name: Paul
Age: 13
I can sing, but I can't dance. I can play the trumpet and the guitar but I can't play the violin.
