double methods of titration

例句：

1. 1.The cost of the new product has doubled compared to last year.
   新产品的成本与去年相比增加了一倍。
2. 2. We need to double our efforts to achieve our goals.
   我们需要加倍努力来实现我们的目标。
3. 3. The price of oil has doubled since the beginning of the year.
   自年初以来，油价已经翻倍。