超速驾驶是导致道路交通伤害的主要原因。事实证明，将平均车速降低1公里/小时可以减少多少致命车祸？
参考答案：
4—5%的致命车祸。
—Only one of these books is worth _______.
—_______ is no wonder that you look so upset.
A．to read; That
B．of reading; This
C．being read; There
D．reading; It
Be quick, _____ we’ll miss the beginning of the fireworks display in the park.
A．so
B．or
C．because
D．though
