《电气化铁路接触网零部件》（TB/T2075.1～2075.54—2002）规定，G

_______ is known to us all is that the 2016 Olympic Games will take place in Rio.[      ]

A. It  

B. Which

C. As 

D. What

An Intranet is (71) the application of Internet technology within an internal or closed user group．Internets are company and not do not have a (72) connection to the Internet．Usedproperly an Internet is highly effective corporate tool，capable of regularly (73) information toempower the workforce with the information needed to perform their roles．Used in this Way，Internet represent a step towards the (74) office．

A．simple

B．simply

C．singlc

D．singly

甲、乙类厂房与民用建筑之间的防火间距不应小于( )。

A．20m

B．25m

C．30m

D．50m

急性化脓性骨髓炎X线平片最早出现征象（）

A.骨质疏松

B.骨质破坏

C.骨膜反应

D.弥漫性软组织肿胀

E.死骨形成

家用沼气灶一次空气进风量的多少，可通过（）来控制。

A、喷嘴

B、引射器

C、调风板

D、火孔