When the star exhausts its usable fuel, it abruptly loses the constant struggle to hold up its own weight.

当恒星耗尽了可使用的燃料时，它会突然失去用以支撑它本身重量的惯有力量。

youdao

But it requires energy to separate the algae from the water and then process the oil they make internally into a usable fuel.

但是这需要能量将藻类从水中分离出来，然后加工成可用燃料。

youdao

India is short of usable uranium. If it could buy foreign fuel for its civilian reactors, it could devote more of the stuff it makes at home to bomb-building.

印度没有可用的铀，如果他可以从国外购买到民用反应堆使用的燃料，那么就可以在家里直接把制造出来东西投入到核弹中。

youdao

Until we actually have a way of turning all the natural gas in the ground into usable fuel for the economy, then this issue will persist (or so it would seem), and sadly the T.

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In Darfur, women must walk up to seven hours, three to five times a week, just to find a single tree with usable firewood to fuel their fires.

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India has since designated some of its reactors as civilian, and open to inspection, but others still churn out spent fuel richly laden with weapons-usable plutonium.

ECONOMIST: Nuclear proliferation in South Asia