上星期我与沃伊坚科通了电话，当时他躲藏在伊斯坦布尔；现在他从陆路去了曼谷。

I spoke to Voitenko last week. At the time he was hiding in Istanbul; now he has gone to ground in Bangkok.

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然后，他们计算出这些光子中有多少一路到达星系际介质中，当时的星系际介质就是氢。

Then, they calculated what fraction of these photons made it all the way to the intergalactic medium, which at the time was hydrogen.

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当时的上海是一座铺着砂石路、房屋低矮的工业城市。

Shanghai then was a gritty, industrial city filled with low-rise buildings.

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