题目

11. In the past few years, my hometown has changed_____ recognition.        A. from                 B. beyond              C. over                  D. with 答案：B写出下列命题的否定:(1)a、b、c都相等;(2)任何三角形的外角都至少有两个钝角;(3)(x-2)(x+5)＞0.