和常规铁路相比，高速铁路对基床表层功能的要求更加严格。
The functional requirements on surface layer of foundation bed for high-speed rail-ways are rather more strict than for ordinary railways.
然而在实践中，我们发现声道的功能早在手术前就没有了，更换表层本身可能会引发声道永久失衡。
In practice, however, we found that function in the canal is often diminished before surgery, and replacing the covering itself may lead to inactivation of the canal anyway.
该深层结构多半可以通过单位词的转换功能映现为主动句或被动句的表层结构。
The deep structure can mostly be presented as the surface structure made up of an active sentence or a passive one, by means of the unit noun characteristic of transformation function.
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