在数据库设计中用关系模型来表示实体和实体间联系。关系模型的结构是( )。
A．层次结构
B．二维表结构
C．网络结构
D．封装结构
参考答案：B
It is important to pay your electricity bill on time , as late payments may affect your（）.
A. condition
B. income
C. credit
D. status
—Is there a fog in the evening ?
—There be . I’ll make a phone call to find it out .
A．must
B．would
C．will
D．might
