Grimm's major contribution to historical linguistics is his explanation of the relationships among cognates in terms of a soundshift, the systematic modification of a series of phonemes.
格里姆对历史语言学的主要贡献是，他从音变-一系列音位有系统的变异-的角度解释了同源词之间的关系。
2
The shift from silent to sound film at the end of the 1920s marks, so far, the most important transformation in motion picture history.
20世纪20年代末无声电影向有声电影的转变标志着迄今为止电影史上最重要的转变。
3
It is similar to how the sound of a train's whistle seems to shift as it recedes into the distance.