中考英语：序数词前加定冠词与不定冠词的区别
1. the + 序数词，表示第几； a+ 序数词表示又一，再一 例如：The cake is delicious, and I would like a second one. 蛋糕很好吃，我想再吃一块。 2. a number of ... 大量的...; the number of... ......的数量； 例如：A number of students like playing computer games. The number of students is about 1,500 in our school.