主要分水岭

例句：

1. 1. The main goal of the project is to reduce pollution.
   这个项目的主要目标是减少污染。
2. 2. Maintaining good health is the main priority for a happy life.
   保持健康是幸福生活的首要任务。
3. 3. The main reason for the delay was due to unexpected weather conditions.
   延误的主要原因是由于意外的天气条件。