高铁：bullet train
As a bullet train set out from Xi'an north station to Chengdu, a new high-speed rail line in western China opened, greatly reducing travel time.
The Xi'an-Chengdu high-speed railway links two ancient cities, Xi'an, capital of Northwestern China's Shaanxi province, and Chengdu, the capital of Southwestern China's Sichuan province.
The 658-km line is the first high-speed railway to pass through the Qinling Mountain, the dividing line of China's northern and southern region. The initial operation speed is 250 kilometer per hour.
拆解
1 X, CD 分别表示 “西安”和“成都”，中国城市名字一般都用拼音缩写。国外城市，按照发音写。
2 V，表示速度。举一反三，a表示加速度。
