A.49.904
B.49.906
C.49.913
D.49.923
[单选题]A.-2/3B.-8/21C.-8/27D.-2/9
[单选题]A.-2/3B.-8/21C.-8/27D.-2/9
[单选题]A.49.904B.49.906C.49.913D.49.923
[单选题]A.1/2B.1/4C.1/6D.1/8
[单选题]A.1/2B.1/4C.1/6D.1/8
[单选题]A.1/2B.1/4C.1/6D.1/8
[单选题]A.1/2B.1/4C.1/6D.1/8