21st century可讀作“twenty-first century”。

二十一世紀，英語讀作twentyn-first century。

"21st-century" 在英語中讀作 "twentieth-century"。

讀作“twenty-first century”。

The term "21st century" directly translates into English as "the twenty-first century," which is the current period of history we are currently experiencing. In English language use, it's commonly read as "twenty-oh-one," with the 'st' in 'twentieth' often contractible to 'th' when speaking, such as "twenty-oh-one."