在西周时代，“姓”和“氏”是两个概念，“姓”表明血统，“氏”则为“姓”的分支。贵族男子的“字”全称有三个汉字：第一个表示长幼行辈（伯、仲、叔、季等），第二字任意，末一字为“父”字。这说明姓氏名字制度在当时最主要的作用（    ）

A

Mikey：I will(将)meet some friends after breakfast．And I'll go to the supermarket (超市)after that．Do you need(需要) anything, Mom?

Mom：Oh, yes please．We need some chicken for lunch．

Mikey：OK. What about fruit?

Mom：I want some bananas, strawberries, and pears．We can have fruit salad for dinner． Oh, can you get four tomatoes and two carrots too?

Mikey：Sure. I'll buy some chicken, fruit, tomatoes and carrots．Any bread or milk?

Mom：No, we have much．Oh, we don't have eggs．

Mikey：OK．I'll buy some．

Morn：Thank you, Mikey．You can buy ice-cream for yourself．

Mikey：That's great! I like it．

Mom：Let's have breakfast first．

Mikey：OK．

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麻疹病毒减毒活疫苗的广泛接种，显著降低了麻疹的发病率．世界卫生组织已将麻疹列为优先消灭目标．下列相关叙述正确的是（　　）