alert|əˈlɜːt|1)adj.机敏的、2)v.警告
助记：alert（alarm clock闹钟)→警告
形近词：alien外国的，外星人alike同样的，同样地
真题例句:Consumers passionate about a product may create"earned"media by willingly promoting it to friends,and a company may leverage"owned"media by sending e-mail alerts about products and sales to customers registered with its Web site.
