题目

选择正确的答语的序号填在横线上。⑴Look at my new cap. A. Hello, Tim.⑵What color is it?B. How nice!⑶This is my brother, Tim. C. Goodbye.⑷Are you Bobby?. D. Yes, I am.⑸Goodbye. E. It's red. 答案：【1】B【2】E【3】A【4】D【5】C已知数列的前n项和，那么数列（   ）A．是等差数列但不是等比数列 B．是等比数列但不是等差数列 C．既是等差数列又是等比数列 D．既不是等差数列也不是等比数列