当今，地理科学已广泛运用现代地理信息技术，研究的范围、内容、方法都有了重大发展。读图，有关现代地理信息技术运用的叙述，正确的是（    ）。

①用GPS了解各大城市的即时天气    ②用GPS确认南极冰盖最高点的位置

③用遥感技术估测内蒙古雪灾受灾面积  ④用遥感技术统计春运期间的客流量

下表为两位男性患者血常规化验报告单，请将化验结果与正常值进行对比，分析回答下列问题：

阅读理解

      Mr. Smith made many tests with different animals and the monkey was the cleverest of all the animals.

      One day Mr. Smith put a monkey in a room. He also put some small boxes in it. In one of the boxes there was some food. "How long will it take the monkey to find the food?" Mr. Smith said to himself. "Let me wait and see." He left the room and waited outside. Three minutes later, he put his eye to the keyhole. What did he see? He saw the eye of the monkey. The monkey was on the other side of the door and looked at Mr. Smith through the keyhole.

抛物线$y^2=2px\left(p>0\right)$的焦点为F，A、B在抛物线上，且$\angle AFB=\frac{\pi }{2}$，弦AB的中点M 在其准线上的射影为N，则$\frac{\left|MN\right|}{\left|AB\right|}$的最大值为（     ）