And if there are multiple light sources, why does each object only cast one shadow?

而且如果说有多个光源的话，为什么每个物体只有一个影子呢？

youdao

This was already cast as the correct class of product object, so you do not need to cast it yourself.

这时产品对象已经被转换成为了正确的类，所以您不需要自己再次的转换它。

youdao

Thrown to indicate that the code has attempted to cast an object to a subclass of which it is not an instance.

该异常的抛出，表明代码企图把对象的类型转换成一个子类，而该对象并不是这个子类的实例。

youdao

When the hideous creature escapes and kidnaps the object of his affection, a crusade is launched to rescue the helpless woman and cast the terrifying creature back to the depths from which he came.

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