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举一反三
【单选题】In the last two hundred years there have been great changes in the method of production of goods. This is now also true of the building industry; for mechanization has been introduced. System building...
A.
the latter uses ready-made internal features
B.
panels are cast in a level position
C.
the former is used to build walls and floors while the latter to construct bathrooms or bedrooms
D.
the former is more expensive than the latter
【多选题】下列有关楔键的描述正确的是（ ）。
A.
楔键的工作表面是上下表面
B.
楔键联接相比于平键联接，其对中性差
C.
楔键的工作表面是两侧面
D.
楔键联接可以承受单向轴向载荷