气相色谱法常用的固定液有()
A.SE-30
B.PEC-20M
C.ODS
D.OV-17
E.角鲨烷
参考答案：A, B, D, E
Whose calculator is this, ______________?[ ]
A. yours or mine
B. his or her
C. your or my
函数f(x)＝|x2－a|在区间[－1,1]上的最大值M(a)的最小值是________．
