光子没有质量——它们是没有重量的。

Photons have no mass – they are weightless.

《柯林斯英汉双解大词典》

我给各位演示，下落途中，的确是没有重量的，这有个壶。

And I'm going to tell you how I can convince you that as I jump, that I will, indeed, be weightless Here is the bottle.

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“此外”，他说，“这些木偶还有这样的优势：出于一切实践的目的，它们是没有重量的。”

"In addition", he said, "these puppets have the advantage of being for all practical purposes weightless."

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