1.pledge的基本含义是“保证”“许诺”,指许诺做、给予或接受某事或某物,常用于表示以行动或言语作出庄严、正式的担保,如答应资助等。有时可译为“发誓”。pledge引申还可指“祝某人健康”。
2.pledge可用作及物动词,也可用作不及物动词。用作及物动词时,后接名词、动词不定式或由that引导的从句作宾语。还可接双宾语,其间接宾语可转化为介词to的宾语。有时还可以接动词不定式充当补足语的复合宾语。

pledge allegiance to(v.+n.+prep.)
宣誓忠于… promise solemnly to be loyal to (usually sth)
▲pledge allegiance to sth
We pledge allegiance to this flag.我们发誓忠于这面旗帜。

用作不及物动词
▲S+～(+A)
The old man is willing to pledge for him.那位老人愿意为他担保。
用作及物动词
▲S+～+n./pron.
He pledged his honour.他以他的名誉作担保。
I pledged my watch.我以手表作抵押。
She pledged her word and kept it for my sake.她发誓为我保密。
He pledged his support.他答应提供支援。
The knights rose from the banquet table to pledge the King.众武士在宴席上起立举杯祝国王身体健康。
Everyone at the table stood up and pledged the bride and bridegroom.在座的每个人起立举杯祝新娘和新郎健康。
You have to pledge your word to spend the money in the most effective way.你们要保证最有效地使用这笔钱。
They pledged their resolve to do still better in future.他们表示决心,以后要干得更好。
▲S+～+to-v
He pledged never to come back until he had found her.他发誓找不到她就永远不回来。
They pledged to learn from each other.他们保证互相学习。
The government pledged to rehouse the refugees.政府许诺给难民提供新房子。
▲S+～+that-clause 
They pledged that they would carry out the instructions to the letter.他们保证不折不扣地执行这一指示。
They have pledged that any details given to them will remain confidential.他们保证对向他们提供的任何细节保密。
They have pledged that they will always remain faithful to each other.他们发誓他们将永远互相忠诚。
He pledges that he would go by the rules.他发誓说他会遵守纪律的。
He pledged that he would repay the debt within a month.他保证一个月内偿还债务。
Every one on the dairy farm pledged that they would not spoil one pound of milk in the whole year.乳品农场的每个人都保证全年中不糟蹋一磅牛奶。
用作双宾动词
▲S+～+pron./n.+n./pron.
I pledge you my words.我向你保证我说话算数。
▲S+～+n./pron.+to pron./n.
Each member of the club has pledged ￡10 to the collection.俱乐部每个成员都承诺捐款10英镑。
用作宾补动词
▲S+～+n./pron.+to-v
They pledged themselves not to bow before difficulties.他们保证绝不向困难低头。
They pledged themselves never to tell the secret.他们发誓绝不将这秘密告诉别人。
They pledged themselves to look into that problem as soon as possible.他们保证尽快调查那个问题。

pledge, contract, covenant, engage, promise
参见promise条。

pledge to do sth 和pledge oneself to do sth 同义。要表达“保证不做某事”的意思时,在不定式前加not或never。例如:
Tom pledged not/never to tell the secret.汤姆保证决不泄密。

［同义词］ n.  agreement, contract, oath, vow, warranty
［词源］＜古法语plege(发誓,许诺,保证)

pledge用作名词的基本意思是“保证,誓言”,也可作“信物”“抵押品”解,其后可接介词短语或动词不定式作定语,也可接that从句作同位语,从句中的谓语用虚拟语气, that有时可省略。

The government should fulfill its pledge.政府应该履行其诺言。
Take this ring as a pledge of our friendship.收下这枚戒指当作我们友谊的信物。
She left her gold bracelet as a pledge.她留下她的金手镯作抵押品。

pledge, oath
参见oath条。