A:﹣ 25 ,5
B:﹣ 25 ,0)∪(0,5
C:﹣ 25 , π2 )∪( π2 ,5
D:(﹣∞,﹣ 25 ∪5,+∞)
—Excuse me. Could you open the window for me?
— ____________.
使用机械的好处是( )