根据以下材料，回答
A farmer carelessly lost an expensivegold watch in the barn on the farm, where he searched for everywhere but invain. So he put a 16 on the gate of the farm: whoever findsthe gold watch will be 17 100 dollars. Facing the 18 of the handsome reward, people tried their best to look for everywhere. 19 , the grain was piled like a hill along with bales of 20 , so if they wanted to find the gold watch, it would be like fishing fora needle in the 21 .
When the sun set, the gold watch was notfound yet. They took pains but found 22 , so they began 23 the watch was too small, the barn was too large and the straw was toothick. It was getting 24 that they were still unable to find it.So they 25 the temptation of 100 dollars one by one.But only a small boy in 26 clothes was still not discouraged butkept 27 it in the grain. He had nothing to eatthroughout the day. In order to solve the family problem, he was 28 to find the gold watch andlet his parents, brothers and sisters have a full meal. He was 29 in the straw to have a rest 30 he heard a strange"tick-tock". He immediately held his breath and listen 31 . It was quieter in the barn while "tick-tock" 32 clearly. The boy 33 the sound, found the gold watch buriedin the depths of the grain and finally got the 100 dollars. Like the gold watchin the barn, 34 has existed around us and spread in verycorner of life. Only we are calm and 35 look for it can we find it.
A.as
B.while
C.when
D.before