单项选择题
A.60sB.40sC.30sD.20s
A.50℃B.80℃C.70℃D.60℃
A.2~3倍B.4~5倍C.5~6倍D.1~2倍
A.90°B.180°C.270°D.360°
微信扫一扫,加关注免费搜题