题目

He then moved to London, _____ he became famous.  A. which                   B. when                       C. where                      D. why 答案：C直线x+y=1与圆x2+y2-2ay=0（a＞0）没有公共点，则a的取值范围是（ ）A．（0，）B．（，）C．（，）D．（0，）