题目

实数a、b、c、d满足下列三个条件:（1）d＞c  （2）a+b=c+d  （3）a+d＜b+c.请将a、b、c、d按照从大到小的次序排列,并证明你的结论.  答案：解： 由（1）得b＞d＞c＞a() 4. —What should we do to reduce food waste?       一 In a restaurant,only order as as we need and try to eat it up.   A. many   B. more   C. much   D. most