effective distance

例句：

1. 1. The effective distance between the two cities is about 500 kilometers.
   这两个城市之间的有效距离大约是500公里。
2. 2. The effective distance of this new drug from its active ingredient is only 20%.
   这种新药的有效成分与活性成分之间的距离只有20%。
3. 3. The effective distance of the project from the target market is a critical factor to consider.
   该项目从目标市场的有效距离是需要考虑的一个关键因素。