主减速器的功能是升速降矩。
参考答案:错
He was reading his book, completely _______ to the world.
A.lost
B.losing
C.to lose
D.to have lost
一个电热器接在12V的直流电源上产生一定大小的热功率,把它接在某一正弦交流电源上时的热功率为加直流电的两倍,这个交流电的电压最大值为( )
A.V
B.12V
C.V
D.24V