【简答题】造成直流放大器零点漂移的两个主要原因是(1) 变动,(2) 变动。
【判断题】造成直流放大器零点漂移的两个主要原因是 电路静态工作点和工作温度。
【简答题】造成直流放大器零点漂移的两个主要原因是( 1 ) ,( 2 ) 的变化。
【单选题】The reason why the first type of perpetual motion machine cannot be successfully manufactured is ( )
A.
energy can neither be created nor destroyed
B.
the loss of work in the actual process is unavoidable
C.
the only forms of energy transfer are heat and work
D.
not all the heat can be converted successfully
【简答题】请完成以下未完成的勾股数:(1)7______24;(2)8______17.
【单选题】According to the text, what can we learn about aviation fuels?
A.
Biofuels can be used as replacement for vehicles as well as planes.
B.
Neither biofuels nor coals can be used for planes.
C.
The idea of green fuel is to change solar energy into fuels.
D.
The idea of green-fuel, which is only an illusion, is challenged and doubted by scientists.
【简答题】造成直流放大器零点漂移的两个主要原因是(1)___________变动,(2)_______________变动。