A:电动机消耗的电能为U²t/R
B:电动机消耗的电能为I²Rt
C:电动机线圈生热为I²Rt
D:电动机线圈生热为U²t/R
People______better access to health care than they used to,and they're living longer as result.
促胰液素的发现者是( )
我国的外流河多数东流入太平洋,其主要原因是( )