【简答题】The idea of ____was first developed by Roman Jacobson (1896-1982) in the 1940s as a means of working out a set of phonological contrasts or oppositions to capture particular aspects of language sounds...
【单选题】The idea of fighting a noise by making more noise sounds strange, but that's exactly what motor engineers are doing in Germany and some other countries. Car makers' research and development laboratori...
A.
By producing pressure waves going in the opposite direction.
B.
By mixing high frequency sound waves with low frequency sound waves.
C.
By mixing new sound waves with the noise and sending them out together.
D.
By making copies of the unwanted sound waves and letting them out a little later.