挑战极限的英文：
push the envelope

参考例句：

You should challenge the limit and exceed yourself.
你应该挑战极限，超越自我。

push是什么意思：
v. 推；催促；逼迫；推进；推行；扩展，扩大；增加
n. 推，推动；奋进，努力

That is pushing it.
那是在推动它。

Push is informal and is used for the selling of illegal drugs push
是口语用词,指出售违禁毒品

The sprouts have pushed up the earth.
嫩芽把土顶起来了。

rush up; push up
催促

A forceful shove or push.
猛推有力的推或挤

envelope是什么意思：
n. 信封，封皮；外壳

envelope airship
飞船蒙皮

rupture envelope
破裂包络线

adiabatic envelope
绝热包络线

This is a buff envelope.
这是张牛皮纸信封。

Show me the airship envelope.
给我看看飞艇气囊。