1. envelope

1. Mother addressed the envelope.
    母亲在信封上写姓名地址。

1. 包膜：后发现该病毒也可存在于其他疾病,故称为EB病毒(Epsteinbarr virus,EBV),EB病毒属疱疹病毒科,又称人疱疹病毒4型(HHV-4),为双链DNA病毒,完整的病毒颗粒由类核(nucleoid),膜壳(capsid),壳微粒(capsomere),包膜(envelope)所组成,类核含有病毒DNA;

2. 公共查询·英语单词

2. 外壳：汉他病毒属RNA型病毒,病毒呈圆形或卵圆形(如图一),直径约80-115(95)nm,核外被含有脂质之外壳(envelope)所包围,外壳表面有突起,病毒在细胞质内增殖时可产生大量之特殊包涵体.

3. envelope：env; 发现被膜抗原

1. 信封
    An envelope is the rectangular paper cover in which you send a letter to someone through the post.

2. 挑战限制尺度；突破原有底线
    If someone pushes the envelope, they do something to a greater degree or in a more extreme way than it has ever been done before.

    e.g. There''s a valuable place for fashion and design that pushes the envelope a bit...
           在原有尺度上有所突破的时尚和设计受到人们的重视。
    e.g. No cinema director had a more profound effect in pushing the envelope of acceptable family entertainment.
           在挑战家庭娱乐片的接受程度方面，没有哪个电影导演比他的影响更深远。

1. any wrapper or covering

2. a flat (usually rectangular) container for a letter, thin package, etc.

3. the bag containing the gas in a balloon

    Synonym: gasbag

4. the maximum operating capability of a system (especially an aircraft)

    e.g. test pilots try to push the envelope

5. a natural covering (as by a fluid)

    e.g. the spacecraft detected an envelope of gas around the comet

6. a curve that is tangent to each of a family of curves