测量气压高度利用什么关系？
参考答案：
高度与静压关系；
用长、宽分别是3π与π的矩形硬纸卷成圆柱的侧面，则圆柱的底面面积为________．
— Why was Professor Liu thundering in the classroom yesterday?
— A student's interrupting his speech ________ the burst of his anger.[ ]
A. set up
B. set out
C. set about
D. set off
