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问题 多项选择题

下列有关环境噪声现状测量时段安排的表述，正确的有( )。

A．应在声源正常运行工况的条件下进行测量

B．应在选择地在声源非正常运行工况下进行测量

C．每一测点，应分别进行昼间、夜间的测量

D．对噪声起伏较大的情况，应增加昼间、夜间的测量次数

答案

参考答案：A,C,D

单项选择题

"What does the middleman do but add to the price of goods in the shops " Such remarks are aimed at the intermediate operations between manufacturers and final customers. This practice usually attracts a lot of attention from the public and the press and the operation most talked about is what is often called wholesaling.
The wholesaler buys goods in large quantities from the manufacturers and sells them in smaller parcels to retailers, and for this service his selling price to the retailer is raised several percent higher. But his job is made more difficult by retail demand not necessarily running level with manufacturers’ production. Because he adjusts or regulates the flow of goods by holding stock Until required, he frees the manufacturer, to some extent, from the effect on production of changing demand and having to bear the whole risk.
The manufacturer can then keep up a steady production flow, and the retailer has no need to hold heavy stocks, who can call on the wholesaler for supplies any time. This wholesale function is like that of a valve in a water pipe. The middleman also bears part of the risk that would otherwise fall on the manufacturer and also the retailer.
The wholesaler provides a purely commercial service, for which he is too well rewarded. But the point that is missed by many people is that the wholesaler is not just someone adding to the cost of goods. It is true one could eliminate the wholesaler but one would still be left with his function: that of making sure that goods find their way to the people who want them.

A middleman’s work may become difficult because ______.

A．manufacturers run their production on a much higher level

B．market demand may not be the same as industrial production

C．retailers are not necessary in running their retailing business

D．retailers demand lower levels than those demanded by manufacturers
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单项选择题

设随机变量Xi～B(i，0.1)，i=1，2，…，15，且X1，X2，…，X15相互独立，根据切比雪夫不等式. 则

的值

A．≥0.325.
B．≤0.325.
C．≥0.675.
D．≤0.675.
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