问题
单项选择题
Annie Jump Cannon, ________ discovered so many stars that she was called "the census taker of the sky".
A．a leading astronomer,
B．who, as a leading astronomer,
C．was a leading astronomer,
D．a leading astronomer who
答案
参考答案：A
解析：结构识别。a leading astronomer是Annie Jump Cannon的同位语。
