reduce to a skeleton

例句：

1. 1. Thecost of the new car is reduced by20%.
   新车的成本降低了20%。
2. 2. The population has been reduced by halfin the past decade.
   过去十年里，人口减少了一半。
3. 3. The amount of oil usedfor cooking has been reduced to save energy.
   为了节省能源，用于烹饪的油量已经减少。