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钢铁在生产、生活中有广泛的用途．建造上海世博会的中国馆--“东方之冠”的核心筒就是用四根巨型钢筋混凝土制成的，其中用了大量的钢铁．

（1）钢铁属于______（填“纯净物”或“混合物”）；

（2）炼铁厂常以焦炭、赤铁矿（主要成分是氧化铁Fe2O3）、空气等为主要原料炼铁，请写出一氧化碳与氧化铁在高温下反应的化学方程式：______；

（3）每年世界上钢铁的产量很高，钢铁的锈蚀也给人类带来了巨大的损失．铁在空气中锈蚀，实际上是铁跟空气中的______和______共同作用的结果．为了防止钢铁锈蚀，人们常采用______的方法（任写一种）来达到目的．

（4）大多数金属暴露在空气中易被腐蚀，这是因为金属易与氧气发生反应，该反应的实质是______反应．从金属的原子结构看，你认为金属易与其它物质发生反应的根本原因是______．

答案

（1）铁中含碳量较高时，属于生铁，含碳量较低时，属于钢，所以钢铁属于混合物；

（2）一氧化碳与氧化铁在高温下反应的化学方程式为：3CO+Fe2O3

 高温 
.
 
2Fe+3CO2；

（3）铁在空气中锈蚀，实际上是铁跟空气中的氧气和水共同作用的结果；在钢铁表面涂漆、镀一层金属等方法可以防止钢铁生锈；

（4）金属原子最外层电子数少于4个，在化学反应中易失去电子，所以大多数金属的化学性质比较活泼，并能和氧气发生氧化反应；

故答案为：（1）混合物；（2）3CO+Fe2O3

 高温 
.
 
2Fe+3CO2；（3）氧气、水；喷漆；（4）氧化；最外层电子数小于4个，化学反应中易失去最外层电子．

问答题

Greystone Co is a retailer of ladies clothing and accessories. It operates in many countries around the world and has expanded steadily from its base in Europe. Its main market is aimed at 15 to 35 year olds and its prices are mid to low range. The company’s year end was 30 September 2010.In the past the company has bulk ordered its clothing and accessories twice a year. However, if their goods failed to meet the key fashion trends then this resulted in significant inventory write downs. As a result of this the company has recently introduced a just in time ordering system. The fashion buyers make an assessment nine months in advance as to what the key trends are likely to be, these goods are sourced from their suppliers but only limited numbers are initially ordered.Greystone Co has an internal audit department but at present their only role is to perform regular inventory counts at the stores.Ordering processEach country has a purchasing manager who decides on the initial inventory levels for each store, this is not done in conjunction with store or sales managers. These quantities are communicated to the central buying department at the head office in Europe. An ordering clerk amalgamates all country orders by specified regions of countries, such as Central Europe and North America, and passes them to the purchasing director to review and authorise.As the goods are sold, it is the store manager’s responsibility to re-order the goods through the purchasing manager; they are prompted weekly to review inventory levels as although the goods are just in time, it can still take up to four weeks for goods to be received in store.It is not possible to order goods from other branches of stores as all ordering must be undertaken through the purchasing manager. If a customer requests an item of clothing, which is unavailable in a particular store, then the customer is provided with other branch telephone numbers or recommended to try the company website. Goods received and InvoicingTo speed up the ordering to receipt of goods cycle, the goods are delivered directly from the suppliers to the individual stores. On receipt of goods the quantities received are checked by a sales assistant against the supplier’s delivery note, and then the assistant produces a goods received note (GRN). This is done at quiet times of the day so as to maximise sales. The checked GRNs are sent to head office for matching with purchase invoices.As purchase invoices are received they are manually matched to GRNs from the stores, this can be a very time consuming process as some suppliers may have delivered to over 500 stores. Once the invoice has been agreed then it is sent to the purchasing director for authorisation. It is at this stage that the invoice is entered onto the purchase ledger.Required:

(c) Describe substantive procedures the auditor should perform on the year-end trade payables of Greystone Co. (5 marks)
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单项选择题

轴瓦属于（）中的零件。

A.滑动轴承

B.滚动轴承
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