warn的用法：
“warn sb. of/about sth”意思是“针对…而警告某人”;“warn sb (not) to do sth”意思是“告戒某人(不)要做某事”;“warn sb. + that从句”意思是“警告某人说……”。如：They warned the passengers of thieves. (他警告路人小心窃贼) / Iwarn you that you will fail in the coming exams if you are still so lazy. (我警告你：如果你还这么懒在即将来到的考试中你会不及格的。) / He waswarned not to go out in the late night. (他受到警告不要在深夜出去)
Romney wins New Hampshire
China faces diplomatic challenges in 2012
Italians turn to Web to battle tax evasion
“螺旋藻产品”铅超标
各种“茶”
Iran steps up nuke activity as it rallies allies
《夏洛特的网》第三章（上）
Tokyo planning to name islets near Diaoyu Islands
Chinese tourists on Italy ship safe
Landslide kills 25 in Philippines