墨子说：“志不强者智不达。”梁启超说：“有毅力者成，反者败。”这给我们的启示是(        )

如图所示的各电场中，a、b两点的电场强度相同的图是（   ）

Scientists have observed that humans experience happiness from a wide range of stimuli(刺激), from traveling to an ideal destination to redecorating one's home or from winning a game of soccer to eating a delicious meal. Simply watching a favorite television show or laughing at a funny joke can lift a depressed mood. While the happiness produced by such experiences tends to be short lived, a wide social network does promote a more long-lasting state of happiness as a lifestyle.

 Surprisingly, income is not a primary factor in determining a person's level of happiness once the basic needs of food, clothing, and shelter have been met. More important is one's social network. Being socially active may be more effective in increasing one's immunity（免疫力）to illness than a vaccine. Misery may love company, but so does happiness, and having close friends and family is vital to one's overall level of happiness. Even sharing one's home with an animal companion can make a person happier.

【写作内容】

1）用约30个单词概括以上材料的主要内容；

2）用约120个词就“幸福”这一话题谈谈你的理解，内容包括：

⑴幸福对你来说意味着什么？

⑵描写一次给你带来幸福感的经历。

⑶面对学习压力，如何提升自己的幸福感？（至少两点）

【写作要求】

1）作文中不能出现真实姓名和学校名称；

2）不必写标题;

【评分标准】

内容完整，语言规范，语篇连贯，词数适当。

如图所示，OBD三点在同一竖直线上，OD的中点B为圆弧轨道CD的圆心．一小球用长为L=0.1m的不可伸长的细线悬挂在O点，细线能承受的最大拉力恰好为小球重力的2倍．现将小球拉到A点静止释放（细线拉直），小球恰好经过B点，且过B点时细线刚好被拉断．已知小球的运动平面与圆弧轨道CD线在同一竖直平面内，重力加速度g取10m/s²．求：

在台湾中国国民党党史馆，参观者可看到依据20世纪40年代某一历史场景制作的***与蒋介石“欢笑言和版”公仔（如下图）。这一历史场景是（　　）

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