根据短文理解，从A、B、C、D四个选项中选择最佳答案填空。

    Today is Sunday. The clothes at Mr. Wang's Clothes Store 1 on sale. So I want to buy some clothes 2 my grandparents, parents and myself. Let 3 have a look. This yellow sweater is at a very good 4 — only 16 dollars. And it is OK for my 5. For my grandmother I want to buy those black 6. They are comfortable (舒适的). 7 about this white T-shirt? Oh, my father can wear (穿) it to 8 basketball. And there are many socks in all kinds of colors. I know my mother 9 green very much. So I will buy these green ones. For me I 10 a pair of blue shorts.

如图所示是认识浮力的探究实验。

已知m﹣n=﹣3，mn=4．

（1）求（3﹣m）（3+n）的值；

（2）求m⁴+n⁴的值．