《汽车综合性能检测站能力的通用要求》（GB/T17993—2005）规定，汽车综合性

下列行为中，表明投标人已参与投标竞争的是（）。

A.资格预审通过

B.购买招标文件

C.编写投标文件

D.正式提出合同要约

补全对话。

A: Can I help you?

B: Yes, please. 1._____. But what kind of flower shall I buy, roses or carnations (康乃馨)?

    She likes red roses best, and today is Mother's Day.

A: I think carnations are special and better today. They show happiness, sweetness and love.

    They are for mothers.

B: All right. Can I have a look at those carnations?

A: Sure. 2._____?

B: Red.

A: What about these?

B: Great. 3._____?

A: 30 yuan.

B: OK, 4._____. Here is the money.

A: Thank you. Here's the change and a card from our shop to your mom. Best wishes to her!

B: 5._____.

下列哪种营养素缺乏，可引起孕妇巨幼红细胞贫血

A．铁

B．蛋白质

C．叶酸

D．泛酸

E．维生素B₂

Baseflipping碱基翻出

领导的重要职责有哪些？