Interpretation and analysis: First of all, the shadow will follow people at any time, corresponding to crossing the bridge with people. When it rains, because rain clouds block the sunshine, you can't see the shadow, which corresponds to rain. There is plenty of light on a sunny day, and the shadow can't be thrown away if you want, which means that it can't be thrown away on a sunny day, so the answer to this puzzle is the shadow.

Other interesting riddles:

1, what has no limbs and only one head is lethal?

Answer and analysis: Brick (literally, there is only one word "head"; physically, it has only one head without limbs; if it is used to hit people, its lethality is definitely strong enough).

Even if you put the knife rest around your neck, you won't hold its hand tightly. What is this?

Answer analysis: cactus (cactus is notoriously full of thorns, no matter who it is, it will not be happy to hold its hand tightly).