But Lu Su told Chou Yu that Chu-ke Liang had figured out the trick.The next day,Chou Yu asked Chu-ke Liang to talk to him.He aked Chu-ke Liang if he could make 100,000 arrows in 10 days.Chu-ke Liang replied,"I need only 3 days to make the arrows."Chou Yu called the army secretary and sighed a contract with Chu-ke Liang.Chu-ke Liang said,"Starting from tomorrow,in three days send 500 soldiers to the river bank to get the arrows."