下列动物中，运动方式都相同的一组是

如图，弹簧测力计挂着重为10N的合金块，让其浸没水中，使容器内水面由16cm上升到20cm，容器内底面积为50cm²，（取g=10N/kg）。求此时：

（1）容器底受到的水的压强；

（2）合金块的密度；

（3）弹簧测力计的示数。

    Mum and dad are two of the most important people in your life. You probably see at least one of them every day. And they influence (影响) you more than anyone else you meet in your 1ife. So if your mom loves to read, you just might grow up carrying a book wherever you go, just like she does.

    But parents do a lot more than just passing on their hobbies. Mums and dads care for（关心）their children from the minute they were born. So they are the people we should respect(尊敬) and love best. It's very important to stay close, get along, and build a strong relationship with your parents. But not every child knows how to do this. Here are some ways to help you.

    Spend time together. Don't play a computer game or watch TV, ask your mum and dad to play with you. Go outside together, or read a book out loud.

    Be kind. Little things might mean a lot to your mum or dad. You can make your parents happy with a hug (拥抱), a card, or a joke（笑话）. It's also lovely when a child cleans up his or her room without being asked. And if you try not to fight with your brothers or sisters, your parents might be very happy.

    Do your best at whatever you do. You don't have to be perfect, but when you do your best, you make your parents proud(自豪). It makes them happy to see how you're turning into a great kid. Why? Because it lets them know you're doing a good job.

数列{a_n}中，a_n＝－n²＋11n，则此数列最大项的值是____．

设集合S_n={1，2，3…n}，若X是S_n的子集，把X中所有元素的和称为X的“容量”（规定空集的容量为0），若X的容量为奇（偶）数，则称X为S_n的奇（偶）子集．

（Ⅰ） 写出S₄的所有奇子集；

（Ⅱ） 求证：S_n的奇子集与偶子集个数相等；

（Ⅲ）求证：当n≥3时，S_n的所有奇子集的容量之和等于所有偶子集的容量之和．