There are two prevalent theories as to why this is the case

关于这种情况如何解释，有两种比较流行的理论。

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Negative case test scenarios are much more prevalent than positive case (such as message being recognized and processed).

负面案例测试方案比正面案例更加流行(例如正在验证和处理的消息)。

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To develop new methods for estimating the sputum smear-positive tuberculosis case detection rate (CDR) in a country where infection with HIV is prevalent.

寻找艾滋病高发国家的痰涂片阳性肺结核检出率的估算新方法。

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And sometimes, as is the case with the increasingly prevalent mobile supper clubs, you might not even be able to pin down their location.

BBC: Hong Kong��s secret nightlife spots

The Dell case illustrates the perverse short-term view prevalent on Wall Street that dictates that growth must occur continuously, smoothly and linearly every quarter.

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