为了解决蜂窝移动通信网中有限频率资源与不断增长的用户要求矛盾，采取了（）和（）两种技术。
参考答案：小区分裂；频率复用
She was so satisfied with all _________we had done for her son ________she wrote us a letter to praise us for it.[ ]
A. which; what
B. that; that
C. that; what
D. what; that
在WORD的编辑状态，打开了“wl.doc”文档，把当前文档以“w2.doc”为名进行“另存为”操作，则（）。
A.当前文档是wl.doc
B.当前文档是w2.doc
C.当前文档是wl.doc与w2.doc
D.wl.doc与w2..doc全被关闭
