①向量 $\overrightarrow{a}$ ，有| $\overrightarrow{a}$ |²= $\overrightarrow{a}$ ²；类比复数z，有|z|²=z²

②实数a，b有（a+b）²=a²+2ab+b²；类比向量 $\overrightarrow{a}$ ， $\overrightarrow{b}$ ，有（ $\overrightarrow{a}+\overrightarrow{b}$ ）²= $\overrightarrow{a}$ ² $+2\overrightarrow{a}\cdot \overrightarrow{b}+\overrightarrow{b}$ ²

③实数a，b有a²+b²=0，则a=b=0；类比复数z₁，z₂，有z₁²+z₂²=0，则z₁=z₂=0

其中类比结论正确的命题个数为（   ）

   We can not live a modern life without traveling．The fastest way of traveling is by air．With a plane people can travel in one day to places which it took a month or more to get to a hundred years ago．
   Traveling by train is slower than by plane, but people can see the country when they are traveling through．Modern trains have comfortable seats and dinning-cars．They make even the longest journey（旅途） enjoyable．
   Some people prefer to travel by sea when possible．There are large luxury liners（客轮） or river boats．They are not as fast as trains or planes, but traveling by sea is a very pleasant way to spend a holiday．
   Many people like to travel by car．They can make their own timetable．They can travel hundreds of miles or only fifty miles a day, just as their wish．They can stop wherever they want to see something interesting or to enjoy a good meal at a good restaurant, or to spend the night at a hotel．That is why people choose traveling by car for pleasant trips, while they usually take trains or planes for business．

今年年初，宁波动物园有人因逃票翻墙被老虎咬死，人们在为逝者感到惋惜的同时，也感叹要警惕那头一直潜伏着不守规则的心中的“老虎”。对此，你的理解是（    ）

①对自己的行为负责，养成良好的自控能力   ②逃张门票小事一桩，游客被咬是晦气

③对自己的生命负责，提高自我保护意识       ④严格遵守相关规定，提高遵守规则的意识