临床资料：男，67岁，自述反复头晕2年余，加重2天，发作性晕厥，上肢麻木。既往史：脑梗塞3年。临床物理检查：颈部有血管杂音。超声综合描述：胸骨上窝扫查右锁骨下动脉起始段管腔内透声不清亮，可见中等回声（箭头所示），CDFI：局部血流信号充盈缺损，PW：V4．77m／s。CDFI：右椎动脉血流出现红、蓝交替现象；PW：右椎动脉血流频谱收缩期呈反向血流，舒张期呈正向血流。见彩图94。超声提示（）。

A.锁骨下动脉窃血综合征（右锁骨下动脉起始段动脉硬化斑块形成并重度狭窄，同侧右侧椎动脉血流逆行流入右锁骨下动脉）

B.右椎动脉狭窄

C.右椎动脉闭塞

D.右椎动脉正常声像图

补全对话，根据对话语境和提供的首字母，填写正确单词，补全对话。

A: Good morning. Washington Press.

B:Good morning. May I 1. s_____to Mr. Kent,please?

A: 2. H_____the line,please.….I'm sorry Mr. Kent's occupied at present.I'll put

you 3. t_____ to his secretary.

B: Thank you.

C: HeIlo,Mr. Kent's secretary speaking. May I 4.h_____you?

B: Yes. This is Carol Sainsbury speaking. May I leave a 5. m_____for Mr.Kent?

C: Certainly,Miss Sainsbury. May I have your 6. n_____?

B: My number is 56321847.

C: 56321847,I'11 ask Mr. Kent to call you 7. b_____when he's free.

B: Thank you 8. v_____much.

C: You're welcome.