comminution theory

例句：

1. 1. The rocks were crushedby the heavy rain.
   雨水把岩石压碎了。
2. 2. The old books were in such poorcondition that they needed to be fragmented.
   这些旧书的状况非常糟糕，需要被粉碎。
3. 3. The machine was designed to crushlarge stones into smaller pieces.
   这台机器被设计用来将大石头碎成小块。