A coverb appears to be subordinate to a main verb and fulfills a function similar to that of a preposition.
It is words like bāng, as used in the above sentence, that are referred to as coverbs in descriptions of Chinese (and of other languages, like Vietnamese and Yoruba, which have analogous structures).
我我wǒI坐坐zuòsit飞机飛機fēijīaircraft从從cóngfollow上海上海ShànghǎiShanghai到到dàoarrive北京北京BěijīngBeijing去去qùgo(simplified)(traditional) 我 坐 飞机 从 上海 到 北京 去我 坐 飛機 從 上海 到 北京 去wǒ zuò fēijī cóng Shànghǎi dào Běijīng qùI sit aircraft follow Shanghai arrive Beijing go"I travel from Shanghai to Beijing by aircraft.
Not all Chinese coverbs can be used as main verbs, however, especially disyllabic ones such as 根据 gēnjù ("according to"), which on the other hand can be a noun meaning "the basis, foundation (of something said)".
The situation is complicated somewhat by the fact that Chinese has location markers that appear after a noun that are often called postpositions.