无论用作介词还是用作副词，均可表示动态意义或静态意义：(1) 表示动态意义，意为“横过”“到…的另一边”。如：Can you swim across 你能游过去吗 （副词用法）I cam swim across the river in 10 minutes. 我可以在10分钟之内游过河去。（介词用法）(2) 表示静态意义，意为“在…的另一边”。如：My house is just across the street. 我家就在街道对面。（介词用法）We leave Dover at ten and we should be across in France by midnight. 我们10点钟离开多佛，午夜时应能抵达法国那边。（副词用法）
and所连接的两个单数名词作主语，指同一人、同一件事或同一概念时，其谓语动词用单数。例如：My best friend and adviser has changed his mind again.Bread, butter and eggs is typical American Breakfast .If law andsgroupsis not preserved, neither the citizen nor his property is safe.如果不能维持治安，公民和他的财产都不安全。表示时间、距离、重量、体积、金钱的复数名词，作主语时作为整体来看待，谓语动词通常用单数。【例如】Five thousands dollars is quite a large sum of money to me.Fifty miles is too long a distance for one to walk on foot.Ten years has passed but he didn't change at all.</p 产品：澳博培训供货总量：不限产品价格：议定包装规格：不限物流说明：货运及物流交货说明：按订单
