Border、bounds、boundary和frontier均含有“边界，边境”之意。但是有细微差别，以下做详细了解。

Border较为常用，指的是【边界或者边界地区】，国与国之间的边界线或边界线附近的地区。如：to cross the border 穿越边界，a border town/state 位于边疆的城镇/州。

Bounds常用于抽象事物中，表示【界限，限制，范围】，如：the bounds of convention 世俗的束缚。His desire for political power apparently knows no bounds (= seems to be unlimited). 他对政治权力的欲望显然没有止境。

Boundary侧重标示某物的界限或边缘，并将其与其它事物或地方隔开的【真实或想象的线】。如national boundary 国界，county boundary 郡界，the boundaries of human knowledge 人类知识的范围。

Frontier同border，但是更多强调边界地区，即国境和边疆。如：Nepal has frontiers with both India and China.尼泊尔与中国和印度都接壤。a frontier town/zone/post 边陲小镇；边疆地带；边防站。

参考双语例句：

①The Group reiterates the urgent need for the police and the gendarmerie, as well as customs agents at the borders, to be equipped with arms, policing material and vehicles to enable them to establish a reasonable level of internal security and border surveillance.

专家组重申，科特迪瓦警察和宪兵以及边境海关人员迫切需要配备武器、警用器材和车辆，使他们能够建立合理的国内安全和边境监控水平。

②The Government stresses that Israeli practices in the occupied Syrian Golan exceed all legal and moral bounds, the most recent example being the imposition by the Israeli occupation authorities of two years’ house arrest on a two-year-old child, Fahid Lu’ay Shuqeir, on the pretext that he was born outside Israel when his parents were studying in the Syrian Arab Republic.

叙利亚政府强调，以色列在被占领的阿拉伯叙利亚戈兰的所作所为超出了一切法律和道德界限，最近的例子是以色列占领当局对一个两岁孩童 Fahid Lu'ay Shuqeir实施两年软禁，其借口是：这个孩子是其父母在阿拉伯叙利亚共和国学习期间在以色列境外出生的。

③What kind of “cross-boundary” working is being proposed, for example distinguishing between a need to share information, a need to coordinate inputs from several sectors, and a need to develop intersectoral activities.

建议何种“跨界线”合作，例如，对于共享信息的需要、协调各部门投入的需要以及拟定跨部门活动的需要之间应区别对待。

④Delivered At Frontier means that the seller delivers when the goods are placed at the disposal of the buyer on the arriving means of transport not unloaded, cleared for export, but not cleared for import at the named point and place at the frontier, but before the customs border of the adjoining country.

边境交货”是指当货物根据采购商的建议放置时销售商不卸货为出口结关，但在边境指定地点不为进口结关，而在毗连国家入关之前结关。