在选择调节阀是采用气关型还是气开型时，主要考虑的是：当信号压力中断时，应避免损害设备和伤害操作人员。
参考答案：对
有6个座位连成一排，现有3人就坐，则恰有两个空座位相邻的不同坐法有______种．
In our school only teachers are allowed to use this room. And only in this room __ find some good dictionaries.
A．we can
B．can we
C．are able we to
D．we are able to
