A:I don’t know that
B:That’s all right
C:Yes, we’ll have another party
D:No, the party wasn’t held
①转动粗准焦螺旋②转动细准焦螺旋③调节光圈④转动转换器⑤向右上方移动装片⑥向左下方移动装片
+8读作____ -13读作____
+68.8读作____ 712 读作____
正四十六写作____ 负十三点六写作____
由直线x=1,x=2,曲线y=sinx及x轴所围图形的面积为( )