The expression probably began because the jungle is filled with wild animals and unknown dangers that threaten people.

VOA: special.2010.05.16

And we are going to be doing a lot of hiking in the jungle.

我们会在丛林里做许多徒步旅行。

I need 实战 - SpeakingMax英语口语达人

People in business have to be careful if they are to survive the jungle out there.

VOA: special.2010.05.16

They will tell you that it is a jungle out there.

VOA: special.2010.05.16

Mowgli,from a character in "The Jungle Book" by Rudyard Kipling.

VOA: special.2009.07.06

You have probably heard the term "concrete jungle."

VOA: special.2011.04.29

Historian and naval officer Samuel Eliot Morison described the fighting this way in his book "The Struggle for Guadalcanal": "For us who were there, or whose friends were there, Guadalcanal is not a name but an emotion, recalling desperate fights in the air, furious night naval battles, frantic work at supply or construction, savage fighting in the sodden jungle, nights broken by screaming bombs and deafening explosions of naval shells."

VOA: special.2011.06.23

Crashes are not uncommon in Papua province where light aircraft, must navigate soaring mountains covered with impenetrable jungle.

VOA: standard.2009.08.02

Normally,Papua New Guinea, a mountainous, jungle-covered nation, contends with a high incidence of dengue fever and malaria.

VOA: standard.2009.09.14

The military says heavy clashes are taking place as troops advance toward a 30-square-kilometer patch of jungle in which the Tamil Tigers are cornered.

VOA: standard.2009.03.17

They included Nneka, who came from Nigeria to promote her new CD, "Concrete Jungle."

VOA: standard.2010.04.07

His images are filled with Machu Picchu's unique textures, such as the mist wrapping around jungle peaks and massive cut stones fitting perfectly against one another.

VOA: standard.2009.12.15

He says the law of the jungle cannot be tolerated In France.

VOA: standard.2009.09.22

featuring the track "Concrete Jungle." entered the Grammy Hall of Fame.

VOA: standard.2010.07.22

The illegals later moved back, and 'the jungle' was established.

VOA: standard.2009.09.22

Brazilian newcomer Ceu sings Bob Marley's "Concrete Jungle".

VOA: standard.2010.07.22

Besson rejects criticism over the closure, saying the zone, known locally as "the jungle", was not a humanitarian camp but rather a hub for human traffickers and a place where people were exploited.

VOA: standard.2009.09.22