题目

完形填空 Mr. Smith is an old man. He1two big houses and a new car. He has no 2, but he has four3 —two sons and two daughters. One son is4England. His name is Tom. The other son is from America. His name is Jack. One daughter is from China.5name is Fangfang. The other daughter is from Japan. Her name is Mikou. Mr. Smith is not the four children's real6, but he loves them7. The children love him,8. Mr. Smith buys many9for the children. He gives10toys to different children. The boys play with toy cars. The girls play with dolls and tog animals. Mr. Smith and the children are good friends. 如图，已知直线AB，CD，EF相交于点O，若∠AOC=50°，则∠COB的度数等于________．