As Amazon celebrates its 20th anniversary,...

　　...let's take a look at four major challenges it faces on its road ahead.

　　One: slow international growth particularly in China,...

　　...where it's failed to make meaningful headway against Chinese e-commerce giant Alibaba...

　　...and other local players.

　　Two: new challengers in the US,...

　　...with online marketplace Jet.com offering a variety of products at a discount to members,...

　　...and Instacart, a direct competitor to Amazon's Prime Fresh service.

　　Three: the lack of a desirable mobile phone in its portfolio,...

　　...which leaves it completely dependent on others as more shopping moves to mobile.

　　And four: the strong chance that brick-and-mortar retailers like Walmart...

　　...finally develop cohesive and successful e-commerce strategies.

　　Amazon has been enjoying double-digit revenue growth,...

　　...but that growth has slowed in recent years.

　　Its 2010 to 2011 growth of 41% went down to more than half...

　　...to only 20% growth from 2013 to 2014,...

　　...suggesting that some of these headwinds may be impacting the company.

　　特色词汇难度级别HEADWINDS(Noun)7PORTFOLIO(Noun)7COHESIVE(Adj)6RETAILERS(Noun)5MARKETPLACE(Noun)5