煙，蒸汽量在一次呼氣中散發(fā)出的蒸汽、煙霧或類(lèi)似物質(zhì)的量
An amount of vapor, smoke, or similar material released in a puff.
自那時(shí)起，從埃及的木乃伊頭發(fā)到石器時(shí)代的檀香木等有機物質(zhì)的年代都已被確定。
Since then, organic materials ranging from Egyptian mummy hair to Stone Age sandals have been dated.
幻影，幽靈明顯可見(jiàn)但沒(méi)有物質(zhì)的實(shí)體；幻影或幽靈
Something apparently seen but having no physical reality; a phantom or an apparition.
物理學(xué)家們正在研究對環(huán)境危害少的發(fā)電新方法，與此同時(shí)，許多發(fā)電廠(chǎng)也在實(shí)現現代化以減少污染物質(zhì)的釋放量。
Physicists are studying new ways of generating electricity with less damage to the environment. In the meantime, many power plants are being modernized to give off less polluting material.
