如图，CD是⊙O的直径，A、B是⊙O上的两点，若∠ABD=20°，则∠ADC的度数为（　　）

    A businessman, with a lot of money, was walking through a remote(偏远的) area. Upon1 this, a thief followed him, planning to2 his money at a certain time. The businessman(商人) noticed something was 3 and he started to pay much more 4to the thief.

    The businessman asked the thief if he5help find some water nearby, and when the thief went to6 the water, the businessman put all of his7into the thief's bag. Then the thief returned and told the businessman8the water was.9the businessman left to get some water, the thief quickly 10 the businessman's bag. Certainly, there was nothing that the thief 11

    The thief was12 but he still did not give up hope. After some time, the businessman returned and they both 13for a long time. Then the businessman got tired and 14 under a big tree. The thief again checked the businessman's bag and still did not find any money. So the thief 15 that the businessman did not actually have any money with him.

    Finally, they arrived at a city. When the thief went after a job and left his own bag behind, the businessman 16 in and took back all of his own money he had put there17When the thief came back, he was surprised to see that the businessman was 18some jewels with the money in his bag. The thief couldn't 19asking the question, “I didn't know you had money on the 20.” The businessman smiled to him, “Of course you didn't, because it is not yours.”