【单选题】In addition to saving and investment in capital, making an even larger contribution to long-term economic growth in real GDP per person
A.
are technological advances.
B.
is lower current consumption.
C.
is higher current consumption.
D.
is a larger work force.
【多选题】用于交流50Hz额定电压 V以下,直流额定电压 V以下的电路内起通断、保护、控制或调节作用的电器称为低压电器。
【判断题】用于交流50Hz,额定电压1500V以下,或者直流额定电压1200V以下的电路起通断保护,控制或者调解作用的电器称为低压电器。
【单选题】Translate the words into Chinese In addition to structure and properties, two other important components are involved in the science and engineering of materials.
【单选题】用于交流 50Hz 或 60Hz ,额定电压 1200V 及以下,直流额定电压 1500V 及以下电路的电器称为( )。
【单选题】Increased internal leakage, in addition to poor hydraulic system response, and inadequate lubrication, is the result of _____.
A.
pump bearings in poor condition
B.
excessively worn actuator-piston packing
C.
broken directional control valve centering springs
D.
low hydraulic oil viscosity