题目

如图，AE，AD和BC分别切⊙O于点E，D，F.如果AD＝20，那么△ABC的周长为( ) A．20      B．30     C．40      D．50 答案：C根据情况填空Yes, you can. No, you can’t.情况：玲玲生病了1. Lingling: Can I have an ice cream?Mum: ____________________2. Lingling:Can I have these biscuits?Mum:____________________