1.key用作及物动词时,作“用键盘输入”“调整…的音调,定调子”解,后接名词或代词作宾语; 还可作“使与…适应〔适合〕”解,常与介词to连用。可用于被动结构。
2.key up可表示“升高或调整(乐器的)音调”,还可表示“使激动,使紧张”“鼓舞”,后面常接介词about,for,to引起的短语作状语。

key to(v.+prep.)
使…与…一致〔适合〕 make sth accord with sth
▲key sth to sth
They tried to key the programme to a younger audience.他们努力使这个节目适合比较年轻的观众。
◇ 用于be ～ed结构
The farm was keyed to the needs of the local people.农场按当地人的需要作了调整。
Their new factories are keyed to produce the things that their army needs.他们把新工厂设计成适合军工生产的地方。

key up(v.+adv.)
1.升高或调整(乐器的)音调 tighten or loosen the strings of a musical instrument so that the right notes are produced
▲key up
This piano wants keying up.这架钢琴需要调音。
▲key sth up
They keyed a piano up to concert pitch.他们把钢琴的音调升高到音乐会的高音标准。
2.使某人激动或紧张 make sb excited, nervous or tense
▲key sb ⇔ up
The thought of the coming expedition to Tibet keyed them up to a high pitch of excitement.一想到即将去西藏考察,他们都感到极度兴奋。
The coach keyed up the team for the big game.教练鼓励队员以备大赛。
◇ 用于be ～ed结构
The crowd was keyed up for the football match.群众为这场球赛而欢欣。
I was keyed up about the examination.我因考试而紧张。
The manager warned us not to get too keyed up before the big match.领队告诫我们在大赛之前不要太激动。

用作及物动词
▲S+～+n./pron.
I have keyed this sentence three times, and it's still wrong!我把这个句子输入了三次,可是仍然不对。
The company keyed its factories to produce more goods.该公司使他的各工厂能够生产更多的货物。
The concert was a failure because the instruments were wrongly keyed.那场音乐会失败了,因为乐器定错调了。

［同义词］ n. answer, clue, code, explanation, guide, index, interpretation, lead, means, sign, solution

1.key是可数名词,基本意思是开房门、箱子等和上钟表发条等的“钥匙”,引申可表示解决事件或问题等的“关键,线索,秘诀,解法,答案”等,其前用定冠词,其后常接介词to〔of〕引起的短语作定语。
2.key还可作音乐等的“调子,音调”解。引申可表示思想、文章、演说等的“调子,基调,口吻”。
3.key也可作琴、打字机、计算机等的“键,按键”解,其后常接介词of引起的短语作定语。
4.key还可作“要塞,要冲,咽喉”解,其后常接介词to引起的短语作定语。
5.key还可用于另一个名词前作定语,用作形容词表示“极重要的,关键的”。

get〔have〕 the key to the door
到达法定年龄 reach the age of majority
Will you come to my party next Saturday?I'm getting the key to the door.我就到了法定年龄了,下个星期六,你来参加我的成年人聚会,好吗?

key to a problem
解决问题的办法 aspect of a problem that, if dealt with, leads to a solution
The country desperately needs more houses, and the key to the problem, as usual, is money.国家极想建造更多的住房,但通常碰到的问题是钱。

This lock has a special key.这个锁有把特别的钥匙。
This bunch of keys is yours.这串钥匙是你的。
He cried that he had found the key.他大声叫喊找到了钥匙。
I spent ten minutes searching through the drawer for the key, and it was in my bag all the time!我花了十分钟翻遍抽屉找钥匙,原来钥匙一直在我包里。
He left his keys in his bed.他把钥匙遗忘在床上了。
I didn't miss the key until I got home and found it wasn't in my bag.直到我回到家想从包里拿钥匙时,才发现它不见了。
Where is the key to the office?办公室的钥匙在哪儿?
I lost the key to the door.我把门钥匙丢了。
Have you got the key to this door?你有这个门的钥匙吗?
He used his key to open the door.他用钥匙开门。
Transport has always been the master key of trade.运输一向是贸易的关键。
The key to the whole affair was his jealousy.整个事件的症结就是因为他妒忌。
Education becomes the key to progress.教育成为进步的关键。
Diligence is the key to success.勤奋是成功的秘诀。
Diet and exercise are the key to good health.吃规定食物和锻炼是身体健康的关键。
The key to good health is to eat and sleep regularly.保持身体健康的秘诀是饮食和睡眠要有规律。
Gibraltar is the key to the Mediterranean.直布罗陀是地中海的要害。
Her fingers touched the keys of the typewriter speedily and accurately.她的手指迅速而准确地触动打字机的键。
A key is the part of a piano that you touch to make music.琴键是钢琴上用手指敲击的部件，它能使钢琴发出乐音。
Piano keys are either black or white.钢琴键不是黑色的就是白色的。
The instruments were tuned to the key of E.乐器都调为E调。
The letter was written in an angry key.这封信是用愤怒的口吻写成的。
Her speech was all in the same key.她的演说自始至终是一个基调。
I don't know the key to the puzzle.我不知道这个谜语的谜底。
He is a key man.他是个重要人物。
Beijing University is one of the key universities in China.北京大学是中国的一所重点大学。

key of, key to
key的后置定语可由of引起,也可由to引起,其区别是:
1.作“钥匙”解时, of后接“房间,建筑物”等, to后接“门,锁”等
2.作“关键”解时, of后接一般事物, to后接“成功”等结果名词
3.作“…的键”解时,用of,作“通往…的要冲”“…的答案”解时,用to。总之,含有方向、结果等意味时接to,表示所属时用of。