石油由原油和天然气组成，它们似乎来源于海洋沉积物中的有机物质。
Petroleum, consisting of crude oil and natural gas, seems to originate from organic matter in marine sediment.
化学（chemistry）这个词来源于“化学的”（chemical），它是一种非常小的东西的例子，其他更大的东西是由它组成的。
The word chemistry comes from chemical, which is an example of one type of the very small things that other bigger things are made of.
现有的白色二极管同样基于蓝色的光——源于这种颜色的光是用于激发一种由钇铝石榴石组成的磷光层。
Existing white LEDs are also based on blue ones, the light from which is used to excite a phosphor layer made of yttrium aluminium garnet (YAG).
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