过双曲线$\frac{x^2}{a^2}-\frac{y^2}{b^2}=1\left(a>0,b>0\right)$的一个焦点作实轴的垂线，交双曲线于A,B两点，若线段AB的长度恰等于焦距，则双曲线的离心率为（   ）

阅读理解。

      Deciding to take your family to the Walt Disney World Resort in Orlando, Florida is just the start; there are many decisions(决定) you will need to make and the most important may be when is the best time to go to the Disney World. Every day thousands of people visit the four theme(主题)parks. You'll never find a time when the parks are empty, but you will find that some times of year are better than others for you and your family.

      I think the best time to go to the Disney World is the first two weeks of November. We love this time of year because there are fewer people and the weather is warm enough for shorts(短裤)and swimming but not hot when you visit there!

如图是“尾气催化转换器”将汽车尾气中有毒气体转变为无毒气体的微观示意图，其中不同的圆球代表不同原子．下列说法错误的是（    ）