题干
28. __________ no need __________ the radio since I've got used to working with it on.
A：It's; to turn dow
B：It's; turning u
C：There's; turning of
D：There's; to turn off
答案(点此获取答案解析）
D
在点
处的切线与坐标轴围成的三角形面积为（ ）