【正确答案】 C

【答案解析】[听力原文]
   A good dose of willpower is often necessary to see any task through, whether it's sticking to a spending plan or finishing a great novel. And if you want to increase that willpower, a new study suggests, you just simply have to believe you have it. According to the study, what matters most is what we think about our willpower. If we believe it's a finite resource, we act that way. We feel exhausted and need breaks between demanding mental tasks. However, people who view their willpower as a limitless resource get energized instead. The researchers used a psychological assessment tool to test the validity of the study. They asked one thousand one hundred Americans and one thousand six hundred Europeans to grade different statements such as "after a challenging mental activity, my energy is depleted and I must rest to get it refueled again" or "I can focus on a mental task for long periods without feeling tired." Although there was little difference between men and women overall, Americans were more likely to admit to needing breaks after completing mentally challenging tasks. European participants, on the other hand, claimed they were able to keep going. Based on the findings, the researchers suggest that the key to boosting your willpower is to believe that you have an abundant supply of it. Your feelings about your willpower affect the way you behave. But these feelings are changeable, they said. Changing your beliefs about the nature of your self-control can have positive effects on character development. This leads to healthier behaviors and perceptions of other people.
   What is often necessary for carrying through a task?
录音开头提到，良好的意志力(A good dose of willpower)往往是完成任何任务所必需的，C项“坚定的决心”是此信息的同义表述，为答案
   录音未提及A项“一个好的开始”和D项“科学的方法”。B项中的plan虽然在录音中有提及，但不是完成任务所必需的东西。