1．When I was doing shopping in the market the other day，I______an old friend of
mine，who I hadn't met for twenty years.
A．came up B．came over
C．came across D．came down
解析：由题意可知，二十年未见的老朋友是在购物时遇见的，这当然是“不期而
遇”。在四个选项中，come up“发生，走到……附近”；come over“从远处
来，过来”；come across“偶遇，碰到”；come down“降低；失望”；只有C项
符合题意。
答案：C
