气源系统中CT(热敏控制器)是如何控制风扇空气活门的()
A.气动控制
B.电气控制
C.液压控制
D.通过BMC再去控制
参考答案:A
In those days, there was hardly any doubt ______ I would win the game, for all my friends stuck with me.
A.when
B.whether
C.if
D.that
曲面z=x+f(y-z)的所有切平面(其中f可导)恒与一定直线