I met Mr Green ________ I was walking across the bridge, but I didn't say hello to him.

[　　]

I met Mr Green ________ I was walking across the bridge, but I didn't say hello to him.

A. before

B. after

C. until

D. while

(补全对话) 根据对话内容, 在每空填上适当的单词, 使对话完整. 每空1分. (Mr. Brown is a headmaster of a middle school. Kate is his daughter. ) Kate: Hello, 754338. Mr Green: Could I _ to Mr. Brown, please Kate: _ on for a moment, please. I'm sorry he _ here right now. May I _ you Mr Green: That's very kind _ you. I would like to see him as _ as possible, please. Kate: Will you _ able to come the day after tomorrow Mr Green: I think so. What time Kate: _ 9: 00 and 10: 00. Mr Green: OK. That would be _. Kate: I'll _ a message on my father's desk. Mr Green: Thank you very much. Good-bye!Kate: You're welcome!

I met Mr Green ________ I was walking across the bridge, but I didn't say hello to him.

[　　]

I met Mr. Green ________ I was walking across the bridge, but I didn't say hello to him.

1. A.
   before
2. B.
   after
3. C.
   until
4. D.
   while