牵引电动机单次中修时，电枢须做清洗、烘干和浸漆处理。()
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SS8型电力机车磁场削弱为晶闸管分路无级削弱。()
The selection says that trends are toward the______.
A. growth of cities and shrinking of suburban areas
B. growth of both rural and suburban areas
C. shrinking of urban and suburban areas
D. growth of urban and suburban areas
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