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

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

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

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

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