混凝土的配合比为（）时，强度最高。

根据《中华人民共和国招标投标法》，以下有关招标文件的说法中，（）是错误的。

A．针对邀请招标，招标人应当根据潜在投标人的情况和特点编制招标文件

B．国家对招标项目的技术、标准有规定的，招标人应当按照其规定在招标文件中提出相应要求

C．招标文件应当包括招标项目的技术要求、对投标人资格审查的标准、投标报价要求和评标标准等所有实质性要求、条件以及拟签订合同的主要条款

D．招标项目需要划分标段、确定工期的，招标人应当合理划分标段、确定日期，并在招标文件中载明

情景对话。

     根据对话情景和内容，从对话后所给的选项中选出能填入空白处的最佳选项，选项中有两项为多余选项。

W: Welcome! What can I do for you?

M: I'm looking for a necklace for my wife.   1  

W: That is so sweet! I'll help you to find one that she'll love.

M: Really? Thanks!

W: Sure.   2   

M: I think a crystal necklace would be better because it stands for purity, and my wife likes crystals

     very much. W: OK.   3   

M: Hmmm. Let me take a look. It's very pretty, but why is it special?

W: You see, normally a crystal pendant (吊坠)is on a gold or silver chain, but this one is on a 

     fabric string.   5   M: Yeah, I see what you mean. I think I'll take it.   6   

W: No problem. The wrapping will take a little while. Please wait a moment.

A. Can you wrap it for me with purple wrapping paper?    

B. I think this heart-shaped one is special.

C. The crystal one is much more expensive.

D. So which would you like, a gold or crystal necklace?

E. How would you like to pay for it?

F. Tomorrow’s our wedding anniversary.

G. This makes the necklace special so it will stand out from the crowd.

3a²b（2ab³-4a³b+5a⁴）=______．

    它是一座山脉，它位于我国的西南面，它是一座弧形山脉，它的主峰是世界最高峰。这座山脉是_______________。

如果起航时主机油门手柄过快推到最大油门则会（）。

A.起动空气量不足

B.燃油在气缸内燃烧不良，主机负荷轻

C.超负荷运转