然而，这些灾难时极其罕见的。只有在地势条件复杂地势低的地方才会发生。
These events, though, are extremely rare and occur only in low-lying areas with the requisite mix of geophysical conditions.
但是在崎岖地势、苍茫大雪、没有食物、很少保暖衣物的条件下要一直保持希望谈何容易。
But it was hard to stay hopeful lost in rugged terrain, in heavy snow, with no food and few warm clothes.
本机特别适用于地势较平坦、道路条件较好的油区钻探开发。
It is especially suitable for the oil exploring and developing area where surface relief is flat and road condition is better.
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