题目

Eric didn’t feel at ____ease in the party, because he was afraid of losing ____face. A. the; a              B. an; / C. /; the              D. /; / 答案：D选修4—1　几何证明选讲 如图，AB是半圆的直径，C是半圆上一点，D是弧的中点，于E，AC与DE、BD分别相交于M、N．求证：．