选用压力表时，最高压力刻度应为工作压力的（）倍左右。
参考答案：1.5
函数f(x)＝－x4＋2x2＋3的最大值为 ．
—_________! Where is my jacket?
—_________, I don't know. [ ]
A. Excuse me, Yes
B. Excuse, Sorry
C. Excuse me, Sorry
D. Yes, Sorry
