题目

In China, a lot of food is wasted every year and the waste food is e【1】for 200,000,000 people. The food is wasted in restaurants, at home and in schools, etc.In restaurants or at home, people often o【2】or cook too much food. But they can’t eat it up . When they go out of a restaurant, f【3】and happy, they n【4】look back at the uneaten food on the table again. Should Chinese consumers(消费者) feel sorry for the terrible w【5】?In schools, we can often see a lot of students throw food away after m【6】and they only eat the food they like.Everyone is supposed to have enough如图1，在四边形中，，，对角线与交于点，平分．（1）求证：四边形是菱形；（2）如图2，在（1）的条件下，过点作交的延长线于点，连接．若，，求的长．