He took his watch to the pawnshop to exchange it for money.
Tips
history
Pawnshops (当铺) have existed in China since the Southern Dynasties (5th century). The character 当 on old pawnshop signs was written extra large as a recognizable symbol, much like the three-ball sign in the West.
mistakes
当 here is pronounced dàng (4th tone), not dāng (1st tone). 当铺 (dàngpù) = pawnshop, but 当然 (dāngrán) = of course.
