A、<img width="20" height="35" src="http://admintk.100xuexi.com/UpLoadImage/2016-08-23/5bf7a77e-3478-4c3f-8f8b-845793a7917b.png" />
B、1.72
C、<img width="20" height="35" src="http://admintk.100xuexi.com/UpLoadImage/2016-08-23/9113bb2d-d795-4d0f-bf8a-fe286aa2d6d1.png" />
D、1.81
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