This is because if the topics are too difficult it is like planning who out of the first 2,000 of 60,000 students will go to which elite schools and there is a very clear distinction. But if the high achievers number around 20,000 and the distinction is not so clear, then the elite schools will gradually disappear--a kind of carrot-and-stick method of winning.
因為如果題目難，等於是為六萬人中的前兩千名設計，誰可以念北一女、誰可以念建中，鑑別得清清楚楚；如果把分數高的人增加，對好學生的鑑別力比較模糊之後，明星學校就會慢慢消失，而是以軟硬體設備來取勝。