题干
— Mingzhou Bridge was open to traffic in May.
— _________! The traffic in Ningbo is becoming better.
— _________! The traffic in Ningbo is becoming better.
A：Good luck
B：Wonderful
C：Good idea
D：Best wishe
答案(点此获取答案解析）
B
的离心率为
，则它的长半轴长为（ ）