问题补充：
Yesterday I an old friend of mine at the shopping mall.
A. came up
B. came out
C. came across
D. came down
答案：
A. came up
B. came out
(答案→)C. came across
D. came down
解析：考查动词短语：A．came up提出，B. came out出版C. came across遇上，D. came down下来，句意：昨天我在超市遇到了一个好朋友。选C。
