The United States currently has just one high-speed line — a 735-kilometer system serving Boston, New York City, and Washington, DC.
美国现在仅有一条高速铁路线——一条服务于波士顿、纽约和华盛顿特区之间的全长735公里的铁路系统。
2
Product line development. An organization may develop and maintain a line of software or system products, rather than a single one.
产品线的开发组织可以开发和维护一条软件或者系统产品线，而不是单一产品。
3
In general, minor changes in the translation materials are usually isolated risks, unlike functional modifications where one bad line of code can disrupt the stability of the entire system.