| 释义 |
| | | | NOUN | | | | /ˈʌndəˌgraʊnd/ | | | | | 1 | a system of public transport consisting of trains that travel in tunnels below a city . The Underground in London is also called the Tube and in some other cities it is also called the Metro . AMERICAN subway （城市的） | | | | 2 | a group of people who take part in secret and usually illegal activities, especially against a government （尤指反政府的）地下组织 | | |