谢谢您！设∑为平面 x+y+z=1 被三个坐标面所截部分,则曲面积分-|||-(iint )_(2)^1dfrac (1)({(1+x+y))^2}dS= () .-|||-A. sqrt (3)-|||-B. sqrt (3)(ln 2-1)-|||-C. sqrt (3)(ln 2-dfrac (1)(2))-|||-D. sqrt (3)ln 2

谢谢您！