第7题: [单项选择]What has happened to some of Telekom’s projects A. They have been put out to foreign tender. B. They have been cancelled. C. They have been postponed. 参考答案:C 答案解析:[精析] 本题题意为：Telekom的项目发生了什么状况 根据“Our advisers are telling us that a temporary reduction in the number
第25题: [单项选择]Questions 11 to 18 are based on the conversation you have just heard. A. Karen is very forgetful. B. He knows Karen better now. C. Karen is sure to pass the interview. D. The woman should have reminded Karen earlier. 参考答案:A 答案解析:[听力原文] W: I can’t believe Karen is late for such an important occasion as a job interview. I remi
第35题: [单项选择]关系中的元组在组成主键的属性上不能有空值，这属于完整性约束的哪一种规则 A. 实体完整性规则 B. 参照完整性规则 C. 用户定义完整性规则 D. 关系完整性规则 参考答案:A 答案解析:【命题目的】本题主要考查了对完整性约束的理解。 【解题要点】实体完整性规则：关系中的元组在组成主键的属性上不能有空值。参照完整性规则：外键的值不允许参照不存在的相应表的主键的值，或者外键为空值。
