【单选题】American consumers like convenience very much. During the last 50 years, there has been a dramatic increase in such labor-saving devices as automatic washing machines, clothes dryers, dishwashers, foo...
A.
a shortage of labor force in America
B.
people's need to reduce the time spent on housework
C.
Americans' interest in doing housework
D.
the quick change of American family life
【单选题】She hasn't written to me ______.
【简答题】平行管路的管子排列应考虑管路互相的影响。在垂直排列时,输气的在( ),输液的在( );热介质管路在( ),冷介质管路在( )。
【简答题】和传统的杂货船运输相比,集装箱运输的优势是什么?
【单选题】My life has changed a lot during the ____________ years.
【判断题】通常认为,管理信息系统主要解决结构化的决策问题,而决策支持系统则以支持半结构化和非结构化决策问题为目的。
【简答题】平行管路的排列应考虑管路互相的影响。 在垂直排列时,输气的在( ),输液的在( );热介质管路在( ),冷介质管路在( )。