Prepositions

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  • Choose the missing prepositions from the drop-down menus below.
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   about      after      at      for      for      for      in      in      of      of      of      of      of      of      of      of      of      on      to      toward  
There has been a relentless quest to find sustainable energy sources the past decades. One source energy that has thus far eluded scientists is nuclear fusion. This is the Holy Grail clean energy. Generations of physicists have tried to replicate this reaction. Scientists the USA say they recreated the power the Sun a minuscule fraction a second. Powerful lasers blasted a tiny target to create a reaction. The burst lasted just 100 trillionths a second, but it created 10 quadrillion watts power. Ten quadrillion is equal to 1 followed by 16 zeros. The power the scientists created is the equivalent of 6 per cent of all the energy from the Sun hitting Earth's surface any given moment.

Nuclear fusion powers the Sun and other stars. The website cnet.com said it is "a long-sought- panacea many energy and environmental challenges". Nuclear fusion power plants could solve our clean energy conundrum and provide infinite, safe, clean and green power. It could also reverse the damage we do the environment. Physicist Dr Debbie Callahan, who worked the experiment, spoke the breakthrough. She said it is a "huge advance fusion" and a big step generating "a net-positive amount energy". Futurism.com said: "The promise is as lucrative as it has ever been - an infinite supply carbon-neutral energy without ever running the risk a nuclear meltdown."

Back to the nuclear fusion lesson.

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