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  3. The following paragraphs are given in a wrong order, for Questions 1 — 5, you are required to reorganize these paragraphs into a

The following paragraphs are given in a wrong order, for Questions 1 — 5, you are required to reorganize these paragraphs into a

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问题 The following paragraphs are given in a wrong order, for Questions 1 — 5, you are required to reorganize these paragraphs into a coherent article by choosing from the list A- H to fill in each numbered box. The third, the fifth and the last paragraphs have been correctly placed.
[A]The biggest extinction threats of all come from space. Solar flares, asteroid strikes and bursts of gamma rays are what we really need to get through. "Every 300 million years we would expect a gamma-ray burst or a severe supernova explosion that wipes out most of the ozone layer," says Brian Thomas , an expert on intergalactic hazards. Yet these things are so rare that the chance of an extinction event in the next 100,000 years is effectively zero. The same can be said for the threat of a solar flare so powerful that it knocks out all critical infrastructure, because it would take flares 1000 times more powerful than the biggest ever seen.
[B]Mind you, this could be seen as a problem. Probably the greatest threat to an advanced civilisation is technology that runs out of control; nuclear weapons, bioengineering and nanotechnology have all been cited as bogeymen. But disaster expert Jared Diamond, points out that we no longer live in isolated civilisations. Humanity is now a global network of civilisations, with unprecedented access to a diverse, hard-won pool of knowledge already being harnessed for everyone’s protection.
[C]What are the odds we will avoid extinction? In 2008, researchers attending the Global Catastrophic Risk Conference took part in a survey of what they thought were the risks to humanity. They gave humans only a 19 per cent chance of surviving until 2100. Yet when you look more closely, such extreme pessimism is unfounded. Not only will we survive to 2100, it’s overwhelmingly likely that we’ll survive for at least the next 100,000 years.
[D]Take calculations by J. Richard Gott, an astrophysicist at Princeton University. Based on 200,000 years of human existence, he estimates we will likely last anywhere from another 5100 to 7. 8 million years.
[E]We are also unlikely to be extinguished by a killer virus pandemic. The worst pandemics occur when a new strain of flu virus spreads across the globe. In this scenario people have no immunity, leaving large populations exposed. Four such events have occurred in the last 100 years — the worst, the 1918 flu pandemic, killed less than 6 per cent of the world’s population. More will come, but disease-led extinctions of an entire species only occur when the population is confined to a small area, such as an island. A severe outbreak will kill many millions but there is no compelling reason to think any future virus mutations will trigger our total demise.
[F]We should probably work on some anti-asteroid measures, but really humans concerned about the longevity of our species can relax; the view from here is fine.
[G]Fossil evidence is similarly reassuring. Records in the rocks suggest that the average species survival time for mammals is about a million years, though some species survive 10 times as long. It seems there is plenty of time left on our clock. Plus, if you’ll excuse the blowing of our own trumpet, we are the cleverest of the mammals.
[H]The following one will take some luck to avoid. Space is full of rocky debris that acts as an occasional threat to earth. It is widely believed that the impact of a 15-kilometer-wide asteroid wiped out the dinosaurs 65 million years ago. In any 100,000 year period we can reasonably expect an impact from a 400-meter asteroid that will cause damage equivalent to 10,000 megatonnes of TNT. "Not enough to do in the whole civilization, but certainly destroy an entire small country like France, "says former astronaut Thomas Jones, who co-chair NASA’s Task Force ON Planetary Defense. Some might argue that without France there is little hope for civilization anyway, but in reality there is only l-in-5 chance of total wipeo-ut. "Global effects come from an impact roughly every 500,000 years, so the odds are about 20 percent for a catastrophic, civilization-threatening impact within 100,000 years," Jones says.

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