小儿，4个月。突发高热、咳嗽、呼吸困难。医生听诊双肺有中、细湿性啰音。进一步检查外周

增殖性糖尿病性视网膜病变最主要的标志是()

A．视网膜水肿

B．视网膜硬性渗出

C．视网膜的新生血管形成

D．视网膜前膜

E．视网膜内出血

In (66) the strength of the carder signal is varied to represent binary 1 or 0. (67) is a system that can map a name to an address and conversely an address to an name. (68) is a three-way handshaking authentication protocol that it’s packets are encapsulated in the point-to-point protocol. (69) is an approach that enables an ATM Switch to behave like a LAN switch. (70) is an guided media which is made of glass or plastic and transmits signals in the form of light.

A．Coaxial cable

B．Optical fiber

C．Unshielded Twisted-pair Cable

D．Shielded Twisted-pair Cable

( )就是鼓励企业向竞争者学习的一种方法。

A．标准跟进

B．流程图

C．结构重整

D．蓝图技巧

试述灰口铸铁的常规金相检验标准和检验项目。

XJFH-2/35气动小绞车开车后，要先空转（）。

A.10s

B.30s

C.1～2min

D.3～5min