Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?
(1) Two of the interior angles of ABCD are right angles.
(2) The degree measure of angle ABC is twice the degree measure of angle BCD.
参考的答案是C。
但是我觉得应该是E，因为条件（1）和（2）没有明确哪一个角是直角。由四边形内角和为360可知，90，90，120，60可以组成四边形，但是90，90，45，135也可以。
请各位指教。 | 
