main line
US /ˈmeɪn ˌlaɪn/
UK /ˈmeɪn ˌlaɪn/

名词
1.
主线
a principal railway line
示例:
•
The express train runs on the main line.
特快列车在主线上运行。
•
Repairs to the main line caused significant delays.
主线维修导致严重延误。
2.
主管道, 主线
a principal pipeline or conduit for water, gas, or electricity
示例:
•
A burst main line caused a widespread power outage.
主线爆裂导致大面积停电。
•
The city is upgrading its water main lines.
该市正在升级其供水主管道。
在 Lingoland 学习这个单词