根据对话内容，判断正误
Mum: Get up, Mike!
Mike: Mum, what time is it now?
Mum: It's eight o'clock.
Mike: Oh, it's time to go to school. I'm late.
Mum: Don't worry! It's Saturday today.
Mike: I forgot it（忘记）. What's the weather like today?
Mum: It's rainy.
Mike: Can I go to the library?
Mum: No, you can't. It's cold outside. It's only 2 degrees. You can read books at home.
Mike: OK, mum. Where's my schoolbag?
Mum: It's in your study.
Mike: Thank you, mum!
的一个焦点
的直线与椭圆交于
、
两点，则
构成
，那么