a/an [adj] envelope
形容词常可修饰envelope，如brown, large, plain等。
She sealed the letter in a brown envelope.
她把信封装进一个棕色信封里。
覆盖物；包装；包络线；包络面；包络；调制包络；音色包络；音量包络；气囊；气袋
A paper or cardboard wrapper used to enclose letters or thin flat items, especially for mailing.
A paper or cardboard wrapper used to enclose small, flat items, especially letters, for mailing.
装信件或薄包裹的扁平容器(通常为矩形)
a flat (usually rectangular) container for a letter, thin package, etc.
Something that envelops; a wrapping.
任何包装物或覆盖物
any wrapper or covering
A bag containing the lifting gas of a balloon or airship; fabric that encloses the gas-bags of an airship.
与一族曲线相切的曲线
a curve that is tangent to each of a family of curves
A mathematical curve, surface, or higher-dimensional object that is the tangent to a given family of lines, curves, surfaces, or higher-dimensional objects.
A curve that bounds another curve or set of curves, as the modulation envelope of an amplitude-modulated carrier wave in electronics.
The shape of a sound, which may be controlled by a synthesizer or sampler.
The information used for routing a message that is transmitted with the message but not part of its contents.
An enclosing structure or cover, such as a membrane; a space between two membranes
The set of limitations within which a technological system can perform safely and effectively.
The nebulous covering of the head or nucleus of a comet; a coma.
An earthwork in the form of a single parapet or a small rampart, sometimes raised in the ditch and sometimes beyond it.
I put the letter into the envelope and sealed it.
我把信放进信封并封好。
用法提示：envelope 作为名词，指装信件的信封。
She received an envelope with a check inside.
她收到一个里面装有支票的信封。
用法提示：envelope 作为可数名词，表示信封。
He carefully opened the envelope with a letter opener.
他用拆信刀小心地打开信封。
用法提示：envelope 作为名词，这里是被打开的对象。
形容词常可修饰envelope，如brown, large, plain等。
She sealed the letter in a brown envelope.
她把信封装进一个棕色信封里。
The envelope on the table is for you.
桌子上的那个信封是给你的。
固定习语，意为超越常规界限。
The director pushed the envelope with his new film.
那位导演在他的新片中挑战了极限。
grammar · medium
易错句子I put the letter in envelope.
正确表达I put the letter in an envelope.
中文没有冠词，学习者容易遗漏。英语中可数名词单数前需用不定冠词，'envelope' 以元音音素开头，故用 'an'。
grammar · medium
易错句子I need an envelop.
正确表达I need an envelope.
'envelope'（信封）是名词，'envelop'（包围）是动词，两者拼写相近但词性不同，注意词尾 'e'。
envelop和envelope拼写相似，但词性和发音不同：envelop是动词，重音在第二音节；envelope是名词，重音在第一音节。
贴邮票的信封
Please put the letter in a stamped envelope.
请把信放入贴好邮票的信封。
写明回信地址的信封
Include a self-addressed envelope for the reply.
附上一个写明回信地址的信封以便回复。
带衬垫的信封
I sent the fragile item in a padded envelope.
我把易碎物品放在带衬垫的信封里寄出。
装信封
She spent the afternoon doing envelope stuffing for the campaign.
她整个下午都在为竞选活动装信封。
挑战极限
The engineers pushed the envelope to achieve faster speeds.
工程师们挑战极限，以获得更快的速度。
飞行包线
The test pilot explored the aircraft's flight envelope.
试飞员探索了飞机的飞行包线。
突破界限；挑战极限
The new aircraft design pushes the envelope of current technology.
这种新型飞机设计突破了当前技术的极限。
粗略地计算；草草地估算
He estimated the cost on the back of an envelope.
他在信封背面粗略地估算了成本。
我们正在挑战极限。
In the movie 'The Right Stuff', test pilots frequently use the phrase to describe testing aircraft limits.
在电影《太空先锋》中，试飞员经常用这个短语来描述测试飞机的极限。
请把信封给我。
This is a classic line from the Academy Awards ceremony, said before revealing the winner.
这是奥斯卡颁奖典礼上的经典台词，在宣布获奖者之前说的。
Choose the next layer that will help you use envelope with more confidence.
Includes Synonyms & Antonyms
Expand your vocabulary with synonyms and antonyms.
Dictionary facts from AI_FALLBACK, DICTIONARY_API_DEV, ECDICT, WIKTIONARY.