A:根據經驗法則,當一個數目大於十時,應以阿拉伯數字來書寫,而當數目小於十時,則以字來書寫,如 There are 20 students in Class A but only six in Class B. (A 班有 20 個學生,但 B 班只有 6 個學生)。
此外,有關英文的數目書寫方式,還有兩個重要原則必須遵守:一是,若以數目做句子的開頭,則該數目須以字來書寫,所以問題中合乎慣用書寫原則的例句是 Twenty-eight people were killed in the train crash. (有 28 人在火車車禍中喪生);另一是,在句子中,數目的表示法或書寫方式必須前後一致。這意謂,必要時可能要改寫句子以使數目出現在句子的走文中,而非句子的開頭。
再者,吾人一定不想以又臭又長的數目「字」來做句子的開頭,如 Five thousand three hundred and twenty people attended the basketball game. (有 5320 人觀看這場棒球賽),若遇到這種情況,強烈建議改寫成像 There were 5320 at the game. 這樣的句子。