Definition: the system of underground trains in London Level: B1
我通常乘地铁上班。
I usually take ___the ___tube to work.
对于首次来访者，乘坐地铁可能令人困惑。
Navigating ___the ___Tube can be confusing for first-time visitors.
高峰时段，地铁非常繁忙。
During peak times, ___the ___Tube gets very busy.
