如果顺时针转30°,记作-30°,那么逆时针转25°,记作______.
根据题意得:顺时针转30°,记作-30°,那么逆时针转25°,记作+25°.
故答案为:+25°.
安全阀定压Ps为1.52MPa,天然气泄放量1.5×104m3/h,温度18℃,选用弹簧全启式安全阀,安全阀所需最小喉径为()mm(天然气摩尔成分:CH496%,C2H60.8%,C3H80.2%,CO22.8%,N20.2%,K取0.7,Z取0.97)。
A.38.5
B.39.5
C.42.5
D.46.5
Does she _________ a biology class today?[ ]
A. have
B. do
C. has
D. does