轴承温度计是测量风压用的。
参考答案:错
B.周期可能是0.4s
C.波速可能是6m/s
D.波速可能是5m/s
---What are you going to do this weekend ?
--- Well, we’ll clean up the city parks ________ it rains..
A.if
B.until
C.while
D.unless