“花钟”的开放时间是怎样的？

圆周率表示一个圆的____和____的倍数关系。π约等于____。

A: Good afternoon! How are you?

B: Fine, thank you. Oh, that's Tom speaking.

A: You're right.____

B: Sure,but she is doing her homework. Wait a moment. Lucy, it's Tom.

(After Lucy answers the phone. )

C: Hello. Tom.

A: Hello, Lucy.____

C: I have no idea. How about you?

A: I'm going fishing nearby on Saturday. Would you like to go with me?

C: ____ I'm sure we can have fun together. By the way, How can we get there?

A: ____ It's not far from here.

B: Sounds good. ____

A: Let's make it 8 :00 am at the school gate. OK?

B: OK. See you then.

A: See you.

10mL NO、CO₂的混合气体通过足量的Na₂O₂后，气体的体积变为5mL（相同状况），则CO₂和NO的体积比不可能为（　　）

下列各句关于文学常识的表述有误的一项是（   ）