Why are mobile phones popular in China, according to the speaker a. They are considered as fashionable items. b. They keep people closer to each other. c. They are more convenient to users than fixed phones. d. They are considered time-saving devices.

建设单位办理工程质量监督手续，应提供的文件和资料包括（）。

A.土地规划许可证

B.施工承包合同

C.施工单位资质等级证书

D.设计单位资质等级证书

E.工程勘察设计文件