Don't push the envelope.

不要挑战极限。

youdao

Test pilots try to push the envelope.

试飞员尝试挑战极限。

youdao

When it comes to population density (the number of people per square mile), some cities really push the envelope.

当涉及到人口密度(每平方英里上的人数)，一些城市真的要被挤爆了。

youdao

"It's absolutely necessary that we continue to push the envelope in terms of try to develop new innovative and more natural ways of effectively treating arthritis."

VOA: standard.2010.08.11

Brandon Gutman: What is American Express doing in 2011 to push the envelope on customer service?

FORBES: Why American Express Is Raising The Bar On Customer Service

It has created a cadre of engineers who can push the envelope on products reliably.

FORBES: The Galaxy S4, Samsung's Last Act in Apple's Shadow

For us to push the envelope of what can be done in Antarctica, that felt good.

BBC: Polar express