"mainline" in Chinese (Simplified)
主线静脉注射（毒品）
Definition
“Mainline”通常指主要的路径或路线，比如主要铁路或水管。在俚语中，也指将毒品直接注射进静脉。
Usage Notes (Chinese (Simplified))
名词时常见于技术或交通领域（如“mainline railway”）。作为动词，是俚语且带有负面含义，仅指毒品静脉注射。不要与“mainstream”（主流观念或趋势）混淆。
Examples
The train follows the mainline through the city.
火车沿着**主线**穿过城市。
The mainline supplies water to every house here.
这条**主线**为这里的每家每户供水。
He used to mainline drugs when he was younger.
他年轻时曾经**静脉注射**毒品。
All major trains run on the mainline during rush hour.
高峰时段，所有主要列车都在**主线上**运行。
It's dangerous to mainline any kind of drug.
**静脉注射**任何种类的毒品都很危险。
That small town isn't on the mainline, so trains rarely stop there.
那个小镇不在**主线上**，所以火车很少在那里停靠。