### Chinese: 尽管德尔塔仍然是全世界主要的新冠病毒株，但奥密克戎病例正在数十个国家出现，其中南非为疫情中心。
### English: Although Delta remains the world's leading strain of SARS-CoV-2, cases of Omicron are emerging in dozens of countries, with South Africa at the centre of the pandemic.
### Errors: There is a minor error of incorrect translation has stylistic problems at "SARS-CoV-2". There is a minor error of incorrect translation includes information not present in the correct translation at "the centre of the pandemic".

### Improved English: Although Delta is still the main COVID-19 virus strain of the world, Omicron cases are emerging in dozens of countries with South Africa at the center of the epidemic.