The principal difficulty faced by the schools has been the tremendous increase in the number of pupils.

学校面临的主要困难是学生人数的大量增加。

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While a few countries are making major strides in this regard, the majority are having great difficulty even stemming the rate of increase, let alone reversing it.

虽然一些国家在这方面取得了显著的成果，但大多数国家就连降低（碳排放的）增长率都很难，更别说减排了。

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The basic idea of this method is to increase the % of your body weight that you use in order to increase the difficulty.

这种训练方法主要是在训练中通过加大所用的体重来逐步增加困难级别。

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Foreigners have long gone out of their way to come to the U.S. for the best medical care, and despite an increase in difficulty obtaining visas post Sept. 11, 2001, they continue to do so.

FORBES: Outsourcing Your Health

The researchers deliberately used questionnaire responses written in Italian to increase the difficulty of the task for the English-speaking participants.

FORBES: Why Bad Weather Is Good for Productivity (Blizzards Notwithstanding)