题目

第三部分：阅读理解（共20小题，每题2分，满分40分） 阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。 A     A Chinese graduate’s record – setting $8,888,888 donation to his school at Yale University has caused wide debate at home. The donation will primarily help build the new SOM campus, while part of it will provide scholarship support for the International Relations Program at Yale's new Jackson Institute of Global Affairs, as well as fund(资助) a variety of China-related activities at the university.     Some a如图，AB是⊙O的直径，∠ABC=30°，OA=2，则BC长为（ ）A．2B．C．4D．