当一个查询基于多个表时,这些表之间必须是______。
参考答案:有联系的
解析: 当一个查询基于多个表时,这些表之间必须是有联系的,查询设计器会自动根据联系提取连接条件。
15. Nowadays with the development of science, more and more new technology_______to the fields of IT.
A.has introduced
B.was introduced
C.will introduce
D.is being introduced
My brother is going to look for another job the company offers him more money.
A.after
B.besides
C.unless
D.when