煙，蒸汽量在一次呼氣中散發出的蒸汽、煙霧或類似物質的量
An amount of vapor, smoke, or similar material released in a puff.
自那時起，從埃及的木乃伊頭髮到石器時代的檀香木等有機物質的年代都已被確定。
Since then, organic materials ranging from Egyptian mummy hair to Stone Age sandals have been dated.
幻影，幽靈明顯可見但沒有物質的實體；幻影或幽靈
Something apparently seen but having no physical reality; a phantom or an apparition.
物理學家們正在研究對環境危害少的發電新方法，與此同時，許多發電廠也在實現現代化以減少污染物質的釋放量。
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.
