单项选择题
A.3.0; B.3.5; C.4.0; D.4.5
A.S=0.8×0.993D+0.2; B.S=0.8×0.993D+0.1; C.S=0.866×0.993D+0.2; D.S=0.866×0.993D
A.13、5; B.13.5、5,5; C.14、6; D.14.5、6