题目

已知x、y都是正数,且+=1,则x+y的最小值等于(    )A.6                B.4              C.3+2            D.4+2 答案：C解法一：x+y=(x+y)(+)=++3≥2+3,当且仅当=,即x=2+,y=+1时等号成立.解法二：由已知x＞2,y＞1,∴y=1+.∴x+y=1++x=(x-2)++3≥2+3.当且仅当x-2=,即x=2+,y=+1时等号成立. In a typical business situation, women, _______, find themselves bumping their heads on “glass ceiling”, a barrier to their career which is not obvious to the observer, impossible to break through.  A．as they might try B．try as they might C．hardly as they try D．as they try very hard