Communication networks can be classified in terms of their physical arrangement or topologies. Three common topologies are the star, bus, and ring.

通信网络可以按照其物理排列或拓扑结构来分类。有三种常见的拓扑结构：星型、总线型和环型。

youdao

Three common topologies are the star, bus, and ring.

有三种常见的拓扑结构：星型、总线型和环型。

youdao

At least three other parakeet species have established feral breeding colonies: the most numerous is the ring-necked parakeet, now common in many London parks and suburbs.

数量最大的是现在常见于伦敦很多公园和郊区的环颈鹦鹉。

youdao

More than 300 white pelicans, 23 endangered wood storks, 50 other fish-eating birds (great blue herons, cormorants, ring-billed gulls, common egrets), and three bald eagles have died near the lake northwest of Orlando.

CNN: Chemicals killing Florida birds, fish