题干
______ number of students went to visit that school last Sunday.
A：The
B：A
C：An
D：/
答案(点此获取答案解析）
B
______ number of students went to visit that school last Sunday.
A：The
B：A
C：An
D：/
=1（0＜a＜b＝的半焦距为c，直线l过（a，0），（0，b）两点.已知原点到直线l的距离为
c，则双曲线的离心率为（ ）
