题干
.
The fresh water in Canada has one-third of the world’s total, much of ____ is in the Great Lakes.
The fresh water in Canada has one-third of the world’s total, much of ____ is in the Great Lakes.
A：it
B：which
C：that
D：what
答案(点此获取答案解析）
B
知点
分别是椭圆
的左、右焦点，弦AB过点
，若
的周
长为8，则椭圆的离心率为 ( )