envelopeKK [ˋɛnvəˏlop] /ˈɛnvəˌloʊp/发音名词1信封、封套She sealed the envelope and wrote the address on the front.她封好信封,在正面写上地址。2外膜、包覆层、外壳The seeds are protected by a thin envelope of jelly.这些种子外面有一层薄薄的胶质外膜保护。3极限、界限、范围多用于 push the envelopeThe new engine design pushes the envelope of fuel efficiency.这款新引擎的设计把燃油效率推向极限。片语1突破极限、挑战极限Their latest album really pushes the envelope of electronic music.他们最新的专辑真的突破了电子音乐的极限。用这个字练口说→相关片语push the envelope