程控系统的中央信号是现场各种（）设备动作情况在控制室的监视系统中的反馈。 A.传感
题型：单项选择题
问题：
程控系统的中央信号是现场各种（）设备动作情况在控制室的监视系统中的反馈。
A.传感
B.皮带机
C.犁煤器
D.除铁器
题型：单项选择题
根据短文内容，用方框中所给词的适当形式填空，并用其正确形式填空，使短文完整，正确。（每个词只能用一次；共10分，每小题一分）
Light travels at a speed(速度) which is about a million times faster than that of sound .小题1:
One second, light travels about 300000 kilometers, but sound travels only 340 小题2: . You can get some idea of this difference by 小题3:________ the start of a running match. If you stand far away from the starter(发令员), you can see smoke小题4:________ from his gun before the sound reaches your ears.
The 小题5: speed of light produces some strange facts. The 小题6: star is so far away that light which you can see from it tonight started to travel to you four years 小题7:________ at a speed of nearly two million kilometers every minute. The light from some of tonight's started on小题8: ________ journey towards you even before you were born.
So, if we want to be honest(诚实), we can not say , " The stars are shining 小题9: ________tonight." We have to say, " The stars look nice. They were 小题10:_______ four years ago but their light has just reached our earth. "