据报道，世博会的安保，将是上海历史上最严格的安检。世博园区外有两道安检门。在园区外围控制区围栏入口，安检员将对入园者进行门票预检和物品抽检。请看上海日报相关报导：Visitors to the World Expo should expect at least two rounds of security checks before they can enter the site, local police officials said yesterday.The first barriers, located around a 4.5-square-kilometer area in the Expo zone, will subject random visitors to spot checks.世博会期间，进园参观的游客需要接受至少两次安检。第一道安检处设在园区内，占地4.5平方千米，这里安检员会随机对一些游客进行检查。上文中的spot check就是“抽查、随机检查、突击检查”的意思，例如：The campaign against drinking and driving will include spot checks on motorists.禁止酒后驾车的行动中将包括对司机展开突击检查这项内容。subject visitors to spot checks这个短语中，subject意为“使服从、使遭遇”，例如：subject him to his superior's will,使他受他上级的支配；而作为形容词，be subject to可以表示“易受……影响的”，如：Japan is subject to earthquakes. 日本经常发生地震。The prices are subject to change. 价格会经常变动。