“by subway” 表示乘地铁、坐地铁这一出行方式(说明交通工具/方式)。
/baɪ ˈsʌbweɪ/
“by + 交通工具”是英语里表示“以……方式出行”的常见结构(如 by bus/by train)。subway 原指“地下通道”,在美式英语中常指“地铁”;因此 “by subway” 直译为“通过地铁(这种方式)”。
I go to work by subway.
我坐地铁去上班。
Because the roads were blocked by heavy traffic, we decided to travel across the city by subway, which was faster and more reliable.
因为路上堵得很厉害,我们决定坐地铁穿过城市,这样更快也更可靠。