propagation of singularities

例句：

1. 1. The news of the new product has been spreading rapidly across the city.
   新产品的消息正在迅速传遍整个城市。
2. 2.The disease is propagating from farm to farm.
   这种疾病正在从农场到农场传播。
3. 3. The seeds were carefully sown and the propagation was successful.
   种子被小心播种，繁殖成功了。