用括号内所给单词的适当形式填空

已知向量$\overrightarrow{a}$，$\overrightarrow{b}$，$\overrightarrow{c}$满足|$\overrightarrow{a}$|=4，|$\overrightarrow{b}$|=2$\sqrt{2}$，$\overrightarrow{a}$与$\overrightarrow{b}$的夹角为$\frac{\mathrm{\pi }}{4}$，（$\overrightarrow{c}$﹣$\overrightarrow{a}$）•（$\overrightarrow{c}$﹣$\overrightarrow{b}$）=﹣1，则|$\overrightarrow{c}$﹣$\overrightarrow{a}$|的最大值为（　　）

我国宪法第一条规定：“中华人民共和国是工人阶级领导的、以工农联盟为基础的人民民主专政的社会主义国家。”这是对我国（   ）

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      It's Sunday afternoon. It's my son's eighth birthday tomorrow. I go into a cake shop to buy a big birthday cake for him.

      When I get there, the shop is full of people. When I am looking for a cake, I find a little boy watching the cakes for a long time. He is in poor clothes. At last he picks a cake. Then he gives money to the salesgirl and says to her, “I want the small cake.”

  “Sorry, the cake is 20 yuan, but you only pay 10 yuan.” says the salesgirl.

  “I …I have no more money.” says the little boy and he begins to cry. “Oh , my boy. Who would you like to buy the birthday cake for?” I ask.

 “My mom, madam.”

“Why doesn't she come and buy one?”

 “My father left us a few years ago,” the boy says. “we don't have money. My mother has to work from morning to night every day. She celebrates my birthday every year, but she never celebrates her birthday. It’s her birthday tomorrow. I want to buy a small cake for her. But I don’t have enough money…”

  “Oh, my boy! I’m your mother's friend,” I say. “I will buy her a nice birthday cake.”I give the money to the salesgirl and leave the shop.