关于SAT语法改错一题

原句:"During my most recent trip,I came across a wonderful store [wandering] in the old quarter of the city."
答案选D.原因:"wandering" 前面漏了一个连接词 (conjunction) :"while" (正在):
修正后:"During my most recent trip,I came across a wonderful store [ while ] wandering in the old quarter of the city." [ 当我这个城市...]
注:只有人能 "wandering".如果没有连接词 "while",那 的不是人,而是 "a wonderful store" 了.