附表:
P(K2≥k)
0.050
0.010
0.001
k
3.841
6.635
10.828
A:0.1
B:0.05
C:0.01
D:0.001
若a是负数,则下列各式不正确的是( )
下列河流被俄罗斯誉为“母亲河”的是( )
A. doesn't B. didn't C. haven't D. hasn't