21的英文怎麼寫序數詞

The battle would start the next morning — Sunday, July twenty-first.

這場戰役就要在第二天早晨,即7月21日星期日打響。

But in the twenty-first century, a very different story is unfolding.

但在21世紀,呈現在大家面前的又是另外一種故事

I have no doubt that America can compete-and succeed-in the twenty-first century.

毋庸置疑,我認爲美國有實力參與21世紀的競爭並取得成功。