根据句意及首字母提示填空。

1. That T-shirt is too short. I want this l________ one.

2. —Do you want these blue p________ ?

    —No, I don't.

3. These socks are very cheap. They're only two d________ .

4. The rainbow has seven c________ .I really like it.

运动会的百米赛跑，终点计时采用以下哪种方式开始计时误差较小[ ]

A．听到枪声时

B．听到发令员的哨声时

C．看到运动员起跑时

D．看到发令枪冒烟时