In the following cases, it is () A. The athlete shoots on the basketball court B. The athlete uses the run-up long jump C. He is soaked to the skin.

A, when the basketball player shoots, because of inertia, the basketball can fly to the basket after leaving the hand, so it is beneficial, that is, A does not meet the meaning of the question;

B, the athlete's run-up in the long jump, that is, the original athlete is in motion, and after taking off, due to inertia, it is conducive to jumping further, so B does not meet the meaning of the question;

C, the dog makes the water on his body in motion by shaking his body, that is, because of inertia, water droplets can be thrown out by the dog's shaking, so it is beneficial, so C does not meet the meaning of the question;

D, if people get off the bus when the car is not stable, that is, people are moving, and the movement stops as soon as people's feet touch the ground, while people's upper body is still moving because of inertia, so it is easy to fall people down, so it is harmful, that is, this option meets the meaning of the question.

So choose D.