一个圆锥的母线长是底面半径的2倍，则侧面展开图扇形的圆心角是（    ）

A．60°

B．90°

C．120°

D．180°

看图补全对话。

1. A:         _ _____ you go yesterday?

    B: I went to Nanjing.

    A: _____ ____ you do?

2. A:              you go to Beijing by train?

    B: No, I didn't.

    A:           did you go there?

    B: By _        .

3. A:         _ do you feel?

    B: I feel sick.

    A:            ?             

    B: I           .