单选题
There are other cases. The cases are the lessons of the past. They should have been obvious. Sadly they are not learned.
【正确答案】
C
【答案解析】[解析] choppy sentence是指多个简单，不连贯的句子。它书写起来比较简单，但是表现出的思路是不连贯的。这里的四个非常简单的句子放在一起显得杂乱无章，读起来很不顺畅，这四个句子完全可以改写成一个句子，那就是The other lessons of the past which have been obvious are not learned．