Childhood obesity has been increasing in recent years. For a long time, the main ways to prevent it have focused on encouraging healthy eating and regular physical activity. Now, researchers at Yale suggest another important factor should be added: reducing stress in parents.

A research team led by Yale psychologist Rajita Sinha found that lowering parental stress may help reduce the risk of obesity in young children. “It’s the third leg of the stool,” Sinha said. “We already knew that stress can be a big contributor. The surprise was that when parents handled stress better, their parenting improved, and their young child’s obesity risk went down.”

To explore this, researchers conducted a 12-week study with 114 parents. All had children between two and five years old who were overweight. Parents were placed in one of two groups. One group took part in a program called Parenting Mindfully for Health (PMH). It taught mindfulness and self-control skills, along with guidance on healthy nutrition and physical activity. The other group received only counseling on nutrition and exercise. During the program, researchers recorded parent stress levels and measured the children’s weight.

By the end of the study, only the PMH group showed lower parent stress, improved parenting, and less unhealthy eating in their children. Three months later, these children did not show significant weight gain. In the control group, parents did not experience these improvements. Their children gained more weight and were six times more likely to fall into a higher obesity risk category.

1.1.How does the author introduce the topic?

A By telling a story.

B By presenting a fact.

C By describing a scene.

D By quoting a saying.

解析：选B。B细节理解题。文章开篇直接陈述“Childhood obesity has been increasing in recent years.”（近年来儿童肥胖症日益增多），这是客观存在的现实情况，作者以此作为切入点引出话题，并未使用故事、场景描写或引用名言的方式。因此，作者是通过呈现事实来引入主题的。故选B。

2.2.What does the underlined phrase “the third leg of the stool” mean in paragraph 2?

A A basic skill.

B A key factor.

C A common issue.

D A vital organ.

解析：选B。B词义猜测题。划线短语“the third leg of the stool”出现在第二段，前文提到长期以来预防儿童肥胖的主要方式是健康饮食和规律运动，而耶鲁大学的研究者认为还应增加“降低父母压力”这一重要因素。结合语境，研究者将父母压力管理比作凳子的第三条腿，意在说明它是与另外两个因素并列的另一个关键要素。因此，该短语在文中意为“一个关键因素”。故选B。

3.3.What can be inferred about the control group?

A They got no stress management guidance.

B They improved their parenting skills.

C They accepted mental health training.

D They reduced their pressure obviously.

解析：选A。A推理判断题。根据第四段内容，实验组（PMH小组）接受了正念、自我调节技能以及营养和运动方面的指导，而控制组只接受了营养和运动方面的咨询。结合实验结果可知，控制组的父母压力没有降低，育儿方式未改善，孩子体重增长更多。由此可以推断，控制组未接受压力管理方面的指导，这是导致其效果不佳的关键原因。选项B、C、D均与文中对控制组的描述相反。故选A。

4.4.What does the study show about the PMH program?

A It lowers children’s sports interest.

B It increases parental pressure levels.

C It prevents children’s excessive weight gain.

D It worsens children’s unhealthy eating.

解析：选C。C细节理解题。根据第四段，PMH项目结束后，“these children did not show significant weight gain”（这些孩子没有出现显著的体重增加），且三个月后他们落入更高肥胖风险类别的可能性更低。文章最后也指出该项目有助于保护儿童免受压力对体重增长的负面影响。因此，研究表明PMH项目能够防止儿童过度增重。选项A、B、D均与文中对该项目效果的描述相反。故选C。