If the virus had been capable of spreading through the air, or if one infected person had unknowingly entered a large population center, Ebola might have become a worldwide epidemic.
如果这种病毒能够通过空气传播，或者如果一名感染者在不知情的情况下进入了人口密集的地区，那么埃博拉可能已经成为一种全球流行病。
Besides striking closer to a major population center, the 6.3-magnitude Christchurch earthquake had a depth of just 5 kilometers (3 miles).
这次6.3级的地震发生在人口密度较集中的赖斯特彻奇市附近，而深度只有5公里(3英里)。
Nuclear energy is a dense form of energy that requires very little in the form of land and transmission lines to carry it to a population center.
核能是高度浓缩的能源形式，只需要很少的土地和有限的输电线路就能将电能输送到人口中心地区。
The ice-free port city of Akureyri lies near the fjord's narrow tip, and is Iceland's second largest population center after the capital, Reykjavik.
拥有不冻港的城市阿克雷里是冰岛第二大的居民聚居地，人口仅次于首都雷克雅未克，它就坐落在这个峡湾的细长的末端。
He worked as a printer, riverboat pilot, reporter, lecturer, and literary man, and he lived in just about every kind of population center, from farms, small towns, and mining camps to great cities.
他曾从事印刷工、河道船舶引水员、记者、讲演者和文学家的工作，足迹几乎遍及每一种类型的人口居住地，其中有农场、小镇，也有矿区营地和大城市。
He worked as a printer, riverboat pilot, reporter, lecturer, and literary man, and he lived in just about every kind of population center, from farms, small towns, and mining camps to great cities.
他曾从事印刷工、河道船舶引水员、记者、讲演者和文学家的工作，足迹几乎遍及每一种类型的人口居住地，其中有农场、小镇，也有矿区营地和大城市。
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