用（）也是把有障碍的控制信号变成一个脉冲信号。
A、单向行程阀消障法
B、换向阀消障法
C、磁性开关消障法
参考答案：A
. ____ I am concerned, we should be brave and we will reach the top of the hill at last ____ we try our best to climb the hill.
A．So long as; as long as
B．As far as; as longer as
C．So long as; as far as
D．As far as; as long as
商品性会计核算软件的特点是什么？
