【判断题】在表设计器中,如果勾选了某个字段的“允许Null值”复选框,则表示这个字段不能取空值。
【单选题】许多航空公司经常200%超售繁忙航线上的机票。
A.
Many airlines irregularly overbook busy routes to as much as 200 percent.
B.
Many airline regularly overbook busy routes by asmany as 200 percent.
C.
Many airlines regularly overbook busy routes by as much as 200 percent.
D.
Many airline regularl overbook busy routes by as much as 20 percent.
【单选题】“表设计器”中的“允许空”选项用于设置该字段是否可以输入空值,实际上就是创建该字段的 ( ) 约束。
【单选题】“ 表设计器 ” 中的 “ 允许空 ” 选项用于设置该字段是否可以输入空值,实际上就是创建该字段的 ( ) 约束。
【单选题】Who will you_____ when you need help ? [ ]
【简答题】A.Exposing oneself to the target culture. B.Drawing up a good language program regularly. C.Doing some reading every morning. D.Developing good note-taking skills.
【单选题】表设计器中的“允许空”单元格用于设置该列是否可输入空值,实际上就是创建该列的( )约束
【单选题】You may ______ your teachers for help when you have problems.
【单选题】在太阳光谱里面为可见光(VL)的波长大约在 () nm。