Astronomers have long speculated that the missing baryonic mass might eventually be discovered in intergalactic space or as some large population of galaxies that are difficult to detect.

天文学家长期以来都在推测，最终可能会在星际空间或者是在难以探测的大量星系中发现丢失的重子质量。

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This is a very subtle error that is difficult to detect and diagnose.

这是一个非常微妙的错误，并且难以检测和诊断。

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The outbreaks will be difficult to detect and control in rural backyard flocks.

在农家后院的鸡群中发现和控制禽流感暴发将是极为困难的。

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Those factors made it very difficult for radar to detect the vessel before it crossed into North Korean waters.

VOA: standard.2009.07.30

Chertoff said an individual or small group planning to do harm is difficult to detect.

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However, carbon-14 is only found in trace amounts, which can make it difficult to detect.

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Carbon monoxide (CO) is difficult to detect because it is colourless and has no taste or smell.

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