adj.無重量的；無重力的
Knowledge is weightless, a treasure you can always carry easily. 知識是一種無重的、可以輕易攜帶的珍寶。
Man is weightless in space. 人在太空失重。
We feel weightless when the elevator descends. 當(dāng)電梯下降時，我們會感到失重。
n.失重
