对于我们这些地球上的普通人，去太空旅行的梦想会成真。
For us common people on the earth, the dream of travelling around space will come true.
当氦衰变成为氦-3相对于我们在太阳里看到的那它就可用了，因为地球上多数的氦-4是通过元素铀和钍自然放射性衰变而造成的。
What helium is available is depleted in helium-3 relative to what we see in the sun, because most of Earth's helium-4 is freshly made via natural radioactive decay of the elements uranium and thorium.
几十年来，危言环境保护主义者一直警告说人类的厄运迫在眉睫，主要由于我们对于地球上自然环境系统的利用不可持续，且对其造成严重影响。
For decades, apocalyptic environmentalists (and others) have warned of humanity's imminent doom, largely as a result of our unsustainable use of and impact upon the natural systems of the planet.
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