在Word中保存文件的快捷键是（）。

下列跨膜运输的生理活动，属于主动运输的是[ ]

A．酒精进入胃粘膜细胞

B．二氧化碳由静脉血进入肺泡内

C．原尿中的葡萄糖进入肾小管上皮细胞

D．水分子出入细胞

— What are your rules for carry-on luggage, Madam?

— You ______ only one piece of luggage on the plane, Sir. [ ]

A. allow

B. allowed

C. are allowed

D. were allowed

An Intranet is (71) the application of Internet technology within an internal or closed user group．Internets are company and not do not have a (72) connection to the Internet．Usedproperly an Internet is highly effective corporate tool，capable of regularly (73) information toempower the workforce with the information needed to perform their roles．Used in this Way，Internet represent a step towards the (74) office．

A．update

B．updated

C．updates

D．updating

SQL语言集数据定义功能、数据操纵功能和数据控制功能于一体。如下所列语句中，哪一个是属于数据控制功能的

A．GRANT

B．CREATE

C．INSERT

D．SELECT

同一个关系模型中可以出现值完全相同的两个元组。