MODIFY STRUCTURE命令的功能是
A．修改库文件的结构
B．修改库文件的类型
C．删除库文件
D．增加新的文件
参考答案：A
解析： 命令 MODIFY STRUCTURE的功能是修改数据库文件的库结构。修改数据库结构包含这样几个方面；增加字段、插入字段，删除字段、修改字段名．改变字段类型。改变字段宽度或小数位数，故选项A为正确答案。
It was time for a holiday! Dawn wanted to go to the beach, but her family had ideas. Where would Dawn’s family go on holiday? One day, Dawn a letter in the letter box（信箱）. It said, “You’ve won!” Dad opened it. Oh, they won a holiday! “I hope it’s to the ,” said Dawn. “I can swim in the sea.” “No, I hope it’s a holiday, ” said Dad. “I can sleep in a tent（帐篷）.” “Well, I’d like to go to a big ,” said Mom. “I can go shopping.” Then they started to argue（争吵）. Beach! Camping! City! They argued（争吵） the evening. Then the phone rang（电话铃响了）. Dawn answered it. “Hello! This is Lucky Holidays. You’ve won a holiday to sunny Alexandria. ” “That’s where my grandma .” “This is Grandma!” “Oh, Grandma, you tricked（戏弄） !” “I invite all of you to spend your summer holiday me.” Two days later, they arrived at Alexandria and spent two weeks at Grandma’s. Dad slept in a tent. Mom went shopping and Dawn swam in the sea. Everyone was happy.
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