证明某因素是某病的病因须经历的步骤是（） A.调查各病例，寻找其共同因素，并用此因素

Network managers have long awaited practical voice-over-IP (VOIP) solutions. VOIP promises ease network management and decreases (66) by converging a company’s telephony and data infrastructures into one network. And a VOIP solution implemented at a company’s head-quarters with far-reaching branch offices can (67) tremendous amounts of money in long distance phone bills, provided that solution delivers POTS-like voice (68) over the Internet.
VOIP gateways are designed to convert voice from the (69) domain to the circuit switched domain. VOIP solutions use a digital signal processor (DSP) to process the voice data, preparing the voice sample for transmission by compressing voice and removing jitter. The VOIP equipment must comply with the (70) H.323 standard defined by the International Telecommunication Union, or ITU.

A．H.320

B．H.322

C．H.323

D．H.324

阅读下面文字，完成后面的题目。    

        踏着晨光，走进了渴望已久的鲁迅故居——百草园。____________刚刚接受过肃杀的冰雪，百草园内却依然一片苍翠葱笼。随风摇曳的竹子，在初生的阳光下，洒落一片淡淡的影子；鲁迅先生儿时摘桑葚吃的老桑树，虽然枝干上被风刀霜箭镂刻得瘢痂交错，但仍然显得____________，生机勃勃。    

（1）上面一段话中有三个错别字，请你找出来并改正。    

①________________________    

②________________________    

③________________________    

（2）下列词语填入横线处最恰当的是（    ）   

A．不管  挺拔巍然    

B．尽管  挺拔巍然    

C．尽管  苍劲傲然    

D．不管  苍劲傲然

胸部CT扫描，肺窗选择是（）

A.W300～500HU、L30～50HU

B.W500～1000HU、L-100～-200HU

C.W1000～2000HU、L-200～-400HU

D.W1000～2000HU、L-400～-500HU

E.W1000～2000HU、L-500～-800HU

下列各项中，属于我国税款征收方式的有( )。

A．查账征收

B．查定征收

C．查验征收

D．定期定额征收