Many foreign supermarkets have entered China, but some have retreated due to their tough times in making profits. CGTN's Zou Yun takes a look at some retailers and how they are doing in China.

Many have come, and some have also left.

China is a vast market filled with opportunities, but for some multinational retailers, it has been difficult for them to operate profitably. For instance, Britain's Tesco left in 2013. And in June this year, French retailer Carrefour sold 80% of its equity interest in its local unit to Chinese retailer Suning for around 5 billion yuan -- that's around 700 million US dollars -- after several years of losses.

But there are also foreign retailers that have not only survived, but also thrived in China. German supermarket chain Aldi opened its first two locations in China in early June. And 20 years since it entered the Chinese market, Walmart has expanded its footprint tremendously. By the end of last year, Walmart had opened more than 400 stores, including over 20 Sam's Clubs, across the country. And one of the secrets behind the boom is the great adjustments they made to cater to the Chinese shoppers' tastes.

STEVEN ZHOU, GENERAL MANAGER SHENZHEN WALMART "We explored the preferences and tastes of ordinary Chinese consumers, and then adjusted our SKUs from 20 thousand to 30 thousand. We even offer deep-fried dough sticks in the morning. In our store alone, we could sell 25 to 30 thousand in one day."

When you're in Rome, do as the Romans do. Or in other words, when you are in China, you have to try hard to meet the needs of the Chinese consumers. Insiders say those supermarkets will not only face competition from multinational chains, but also homegrown chains, including Alibaba's Hema stores, which offer a hybrid of online and offline shopping.

ZOU YUN BEIJING "Experts say that with E-commerce becoming a key driver of consumption growth in recent years, retailers have to integrate online and offline channels to meet their full potential in the digital era. ZY, CGTN, BJ."