对于任何在()米以上高度工作时,有坠落危险的员工,应配备并使用()措施。当在轿顶与井

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问题:

对于任何在()米以上高度工作时,有坠落危险的员工,应配备并使用()措施。当在轿顶与井道之间的距离大于()毫米时就存在坠落危险。

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T细胞的生物功能不包括

A.产生细胞因子

B.直接杀伤靶细胞

C.参与对病毒的免疫应答

D.诱导抗体的类别转换

E.介导ADCC效应

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下列说法正确的是(  )

A.一个数前面加上“-”号,这个数就是负数

B.零既不是正数也不是负数

C.零既是正数也是负数

D.若a是正数,则-a不一定就是负数

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Passage 1In order to produce goods and services, businesses need to buy the required raw materials and equipment. Many firms need to order components or equipment to their own specifications which will later be used to produce a finished product. Firms need reliable suppliers who must be:Stable. Firms that can not supply goods in time to the purchasing company may mean delays and holdups for customers. Thus the purchasing company should check the financial background of its suppliers.Able. The purchasing company must investigate whether potential suppliers are able to make the goods required. This may mean looking at the firm’s equipment and staff expertise if a large or important order is being considered. Some purchasing departments may ask for evidence of the firm having done similar work for other organizations before placing an order. Trade directories and specialist magazines are a useful starting point in this research.Clear. What is required will usually be made clear in a specification. The specification or “spec” will give the exact technical details of what is needed in terms of size, shape, color and performance of the items to be purchased. The supplying firm must then meet this specification exactly.An important problem all purchasing companies have to deal with is whether to use one or two or several suppliers. By using several suppliers it is argued that competition between them will force prices down. And delays or disruption at one supplier will not affect too much. Arguments against this are that researching various suppliers is time-consuming and expensive, and low prices might mean reduced quality. Using fewer suppliers for larger orders can mean that the purchaser receives greater attention and discount for bulk purchases. The suppliers will be more involved in the firm’s business, too.

Supplying firms with rich experience, good equipment and staff expertise can only be found in specialist magazines. ( )

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用来决定在不同预警级别情况下,是否应当发出警报以及发出何种程度警报的是()。

A.预警准则

B.因素预警

C.指标预警

D.综合预警

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下列选项中,不属于夏季四防范畴的是()。

A、防滑

B、防冰雹

C、防雷电

D、防干旱

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