An artist who was recently traveling on a ferry to the southern island discovered a long lost antique Greek vase.
A. at random
B. by chance
C. in turn
D. on occasion
网友回答
A. at random
(答案→)B. by chance
C. in turn
D. on occasion
解析：句意：一个在南部岛上旅行的画家偶然发现了一只古希腊花瓶。at random“任意地，随便地”；by chance“偶然地，意外地”；in return“反过来，作为报答”；on occasion“有时，间或”。
【考点定位】考查介词短语的意义。