历史事件有着不可分割的内在联系。下列对历史事件之间的联系表述正确的是（   ）

①日本偷袭珍珠港——第二次世界大战的爆发      ②斯大林格勒战役——欧洲战场的胜利结束

③国共两党首次合作——北伐的胜利进军     ④九·一八事变——中国抗日战争的起点

若$f\left(x\right)=x^3+3a{x}^2+3\left(a+2\right)x+1$有极大值和极小值，则a的取值范围是 （   ）

学习历史时，学会正确的计算历史年代是很必要的，请问下面年代尺上某事件经历了多少年（   ）

    Most English people have three names: a first name, a middle name and the family name. Their family name comes last. For example, my full name is Jim Allan Green. Green is my family name .My parents gave me both of my other names.

    People don't use their middle names very much. So “John Henry Brown” is usually called “John Brown”. People never use Mr., Mrs. or Miss before their first names. So you can say John Brown, or Mr. Brown; but you should never say Mr. John. They use Mr., Mrs. or Miss with the family name but never with the first name.

    Sometimes people ask me about my name. “When you were born, why did your parents call you Jim?” they ask. "Why did they choose that name?” The answer is they didn't call Jim. They called me James. James was the name of my grandfather. In England, people usually call me Jim for short. That's because it is shorter and easier than James.