You need to write the main idea of each paragraph of the story and if all the mean ideas are about the same topic then you got the main or central idea of the story.
The speed and accleration of a car travelling in reverse and in the normal direction is the same. Therefore the measurement of its speed is still done using the metric system or via miles per hour (mph).
Means to be extremely and under emtional stress can cause the soul to actually leave the body.