He went back to the hall to try his at finding his lost gold watch，but never found it.
A. best
B. success
C. result
D. luck
网友回答
A. best
B. success
C. result
(答案→)D. luck
解析：短语try one’s best(努力,尽力)后常接to do sth.;try one’s luck at doing sth.意为 “碰碰运气做某事” 。B 、C两项不符合题意。