种族背景与成为美国人毫不相干。如果说大多数美国人都来自不同国家，有不同的种族背景，这种假设肯定成立。

To say that the majority of people in the United States have some sort of tie with an ethnic background from a different country would be a safe assumption.

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本文讨论了部分偏振的斑纹图样与一个处在任意偏振态的均匀背景相干迭加的统计性质。

In this article we consider the statistical properties of the superposition of a partially polarized speckle pattern and a coherent background in an arbitrary polarization state.

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由于高分辨率SAR图像中，目标背景复杂，同时由于受相干斑噪声的影响，因此很难直接从原始图像数据中提取道路特征。

Due to the complicated background of objectives and the speckle noise in the high-resolution SAR images, it is almost impossible to extract roads directly from original remote sensing images.

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