I ______have come here in time, but I met an old friend of mine. I stopped and talked with him for some time

1. A.
   shouldn’t
2. B.
   must
3. C.
   needn’t
4. D.
   could

It was at the school gate ______ I met an old friend of mine after class.  

I ___________ in the street when I met an old friend of mine  yesterday.

A．walked           B．was walking        C．has walked        D．had walked

While ___ along the street, I met an old friend of mine.

I met an old friend __________ on the train yesterday.[