Bluetooth is a universal radio interface in the (1) frequency hand that enables portable electronic devices to connect and communicate wirelessly via short-range, ad hoc networks. Each unit can simultaneously communicate with up to (2) other units per piconet. Moreover, each unit can simultaneously (3) to several piconets. Eliminates the need for wires, cables and connectors for and between cordless or mobile phones, modems, headsets, PDAs, Computers, printers, projectors, local area networks, and so on, and paves the way for new and completely different devices and applications. Technology Characteristics (4) symbol rate exploits maximum available (5) bandwidth。

5（）

A．messages

B．certificates

C．applets

D．channel

患者，女，17岁，初潮后月经不规律，先后不定，本次月经提前15天来潮，开始量少，近3天量多，色鲜红，有血块，无腹痛，伴头晕心慌，气短乏力。2月前曾行B超检查，子宫附件未发现异常。

若诊断为无排卵型功血，止血应选择：（）

A.孕激素

B.三合激素

C.诊断性刮宫

D.止血敏

E.雌激素