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
查看答案
三相异步电动机运行时,若转差率为零则电磁转矩也为零。()
烧伤后形成的焦痂进入组织溶解期的时间是伤后()
A. 一周
B. 3~5 d
C. 7~10 d
D. 2~3周
E. 4周
异步电机与同步电机的基本区别是,转子转速与定子旋转磁场的转速不相等。()