The hum of the electric motor deepened by fractions of a tone as he turned the nuts.

他拧紧了螺丝，马达的嗡嗡声极轻微地加大了。

The light and dark patches show differences in temperature by fractions of a degree, revealing where matter was beginning to clump together to form the first galaxies shortly after the Big Bang.

亮斑和暗斑显示温度相差几分之一度，揭示物质开始聚集在一起的位置在大爆炸后不久形成第一个星系。