如图，C是线段AB的中点，CD=BE，CD∥BE．求证：∠D=∠E．

若关于x的一元一次不等式组 无解，则m的取值范围为（  ）

    Johnny Carson began his work in television ____his twenties. First he worked at local stations in Nebraska. Several years ____ (late), he moved to Los Angeles, California. It was “The Tonight Show”____made Johnny Carson famous for thirty years. He became ____most popular star of American television. He ____(call) “the king of late night.” Critics said Americans from all parts of the country liked him and felt they knew him.

    He did not take his fame ____ (serious). For example, when asked how he became a “star”, he answered: “I started in a gas state and I cooled.” Carson's special skill was his sense of humor. Audiences laughed at his jokes he made at the____ (begin) of his show. However, sometimes they laughed even____(hard) at the jokes that failed. He was the most____(power) performer (表演者) on television. Many comedians (喜剧演员) and singers became successful after____ (appear) on “The Tonight Show”.

中国历史上第一部纪传体史书是《____》。