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老师在黑板上书写了一个正确的演算过程随后用手掌捂住了如图所示的一个二次三项式，形式如图：

“二战”后资本主义世界经济体系的三大支柱是（  ）
①世界银行 ②国际货基金组织 ③关贸总协定  ④联合国

    Rick is a good man．He makes birthday cakes in a shop．His cakes are great and have very good prices，so many people buy his cakes．He makes friends with lots of his customers(顾客)．They all like him very much．One evening．he wants to go home，but many of his old customers come in．Rick smiles(微笑)to them，“I am sorry．It is late today．If you need cakes，please come tomorrow．”One of them takes out a nice cake and says to him，“You make so many great cakes for us．This birthday cake is for you．Happy birthday, Rick．”