warn的用法及詞組（warn相關短語）
1. warn SB (not) to do 警告、勸誡、勸說某人（不）要做某事
初高中學習是孩子處于青春期的階段，也是孩子學習當中最關鍵的六年，因為它涉及到了中考與高考，左養中學教育賴頌強再講孩子的學習方法和考試心里調節的直播課里，系統的講解到如何幫孩子提升學習效率，提升考試時候的心理素質，從而提升學習成績。
這個用法可以轉化為被動語態：SB be warned (not) to do ,例如：
The doctor warned the patient not to eat oily food after the operation.=
The patient was warned not to eat oily food after the operation by the doctor.
醫生警告過病人在手術后不要吃油膩食物。
I warned you not to buy that old car.
我勸過你不要買那輛舊汽車。
They wre warned not to climb the mountain in such bad weather.
有人勸誡他們不要在這么壞的天氣去登那座山。
He warned me not to be late.
他提醒我不要遲到。
《牛津高階英漢雙解詞典》
‘I warned you not to phone me,’ he said evenly.
“我告誡過你不要給我打電話。”他平靜地說。
Police are warning the public to be on the alert for suspicious packages.
警方警告公眾要警惕可疑包裹。
Mrs. Blount warned me not to interfere.
布朗特夫人警告我不要插手。
The police warned them not to go out at night.
警察告誡他們夜間不要出門。
He warned Billy to keep away from his daughter.
他警告比利離他女兒遠點。
特別提示：warn sb about/against sb/sth提醒注意（可能發生的事）；使警惕
He warned the tourists against pickpockets.
他提醒游客要提防小偷。
He warned us against pickpockets.
他提醒我們要提防小偷。
The guidebook warns against walking alone at night.
這本指南告誡夜間不要單獨行走。
2.warn of 警告……關于（危險等）；預告說……；通知說
Police have warned of possible delays.
警方已經通知可能會廷期。
Please give us advance warning of any changes.
如有變動，請事先通知我們。
It seems only right to warn you of the risk.
似乎應該警告你有風險。
The motoring organization is warning of thick mist and blowing snow on high ground.
汽車協會預告說在高地有大霧和風雪。
The government has warned of stormy waters ahead.
政府已告誡說，以后的局勢將很嚴峻。
3. warn sb off (sth) （尤指以威脅的方式）叫…離開，告誡…不要靠近；
The farmer warned us off his land when we tried to camp there.
我們想在那里露營時，農場主警告我們不得靠近他的土地。
warn sb off doing勸…不要做；建議…停止做
We were warned off buying the house.
有人勸我們不要購買這所房子。
