女性，40岁，胸痛部位在 * * 外，为刺痛，发作数秒钟，含服硝酸甘油1～2s疼痛消失，最可能的诊断为（）

A.不典型心绞痛

B.心脏神经官能症

C.变异型心绞痛

D.稳定型心绞痛

E.自发型心绞痛

For each blank, choose the best answer from the four choices and write down on the answer sheet.

(1) is a six bytes OSI layer 2 address which is burned into every networking device that provides its unique identity for point to point communication.

(2) is a professional organization of individuals in multiple professions which focuses on effort on lower-layer protocols.

(3) functions with two layers of protocols. It can connect networks of different speeds and can be adapted to an environment as it expands.

(4) is the popular LAN developed under the direction of the IEEE 802.5.

(5) is the popular backbone technology for transmitting information at high speed with a high level of fault tolerance which is developed under the direction of ANSI.

5（）

A．X.25

B．ATM

C．FDDI

D．SMDS