如图所示的装置中，小球的质量均相同，弹簧和细线的质量均不计，一切摩擦忽略不计，平衡时各弹簧的弹力分别为F₁、F₂、F₃，其大小关系是（   ）

方程$\sqrt{{\left(x+3\right)}^2+{\left(y-1\right)}^2}=\left|x-y+3\right|$所表示的曲线是（　　）

学习历史有一基本结论就是“思想文化是一定现实的反映”。“百家争鸣”学术局面反映的社会现实是（  ）

读亚洲东北部图，回答问题。

    When you stay away form your home for a long time, you start to miss your good bed, your good parents. Believe it or not, you're feeling homesick. You can help yourself to feel less homesick. Here's how:

      ⑴   .If you're going away from home, bring your favourite clothes, you can also bring some pictures of the people who you may miss. You can look at them any time you want.

       ⑵   .The busier you are, the less time you'll have to feel homesick. Spend your free time on music, sports or books. Try to join in activities whenever you are.

       ⑶   .You can make a plan for when you'll call your mom or dad. You can also keep in touch with family and friends by email or text messages.

       ⑷   .Sometimes, telling someone that you're feeling a little homesick will help you feel better. Maybe you can tell a friend that you feel homesick and the two of you can do something fun.