所以，现在的目标是有效的转化所谓第二代燃料源——草、木头、纸和来自农作物里但不能吃的废物——使之生产生物燃料。

So the goal now is to efficiently convert so-called "second-generation" sources - grasses, wood, paper and the inedible waste from food crops - into biofuels.

youdao

电子废弃物种类繁多、成分复杂，含有多种有毒、有害物质，已成为固体废物中最大的重金属污染源。

Electronic waste contains different kinds, components and poisonous substances; it has become the largest pollution source of heavy metal in the solid waste.

youdao

铸造生产的两大污染源，一是使用含有有毒物质的树脂黏结剂，二是排放的废砂成为大量固体废物。

In foundry production, two great pollution sources are use of resin binders containing toxic matters and large amount of solid garbage resulting from waste sands.

youdao