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问题 单项选择题

有些非均质的固体如透明软骨、小儿肾锥体，可以出现无回声或接近无回声，所以，少数固体呈无回声，但必须是（）。

A.均质性的

B.非均质性的

C.混合性的

D.与是否均质无关

E.以上都正确

答案

参考答案：A

单项选择题 A1/A2型题

某矿工，男，40岁，因塌方事故时被泥土、矿石压埋致伤。当时不能站立，腰部疼痛无力。双下肢不能自主活动，双腹股沟以下感觉消失，急送医院。正确的搬运方法是（）。

A.搂抱

B.一人背

C.一人抬头，一人抬足

D.三人用手平直托起，保持躯体平直

E.两人抬上肢，两人抬下肢
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单项选择题 案例分析题

Transportation Decision Transportation decision consists of the following parts: 1.Selection of the mode is determined by the consideration of distance,cargo weights,linkage,timing and other requirements.Generally speaking,rail has high fixed cost and the relatively low variable cost.It can move heavy,large quantity of cargo in the long distance.But,rail is disadvantaged because of the longer transit time and less frequent service than motor. Motor carriers such as truck companies offer door-to-door service,that is,the cargo can be shipped from the shipper＇swarehouse to the consignee＇s.Trucking fixed cost is the lowest of any carrier,because the equipment is fairly cheap and the motor carriers do not have to invest in the roads on which they run their operations.However,their variable costs are very high.Its expenses include two major components:firstly,the pick-up and delivery costs;secondly,there are gas or fuel costs,labor expenses and toll roads fees to be paid to highway and toll road operators Therefore,motor transport is good for cargo with small quantity to be shipped within short distances. Water is the predominant choice of transportation as it has the capacity to take greatest quantity,travel longest distance with lowest cost.Transport by sea accounts for 80% of in-ternational trade.The major expenses for water are expenses associated with investment and maintenance of the ships and terminals.For example,a 100000-ton container ship costs US$ 200 million.Terminal associated costs include harbor fees and the cost for loading and unloading the goods. Transport by air has the highest cost but it is fast with the lowest ratio of loss and dam-age.If you need to deliver an urgent order,there is little choice but by air. 2.Transport service provider is selected for its experiences,equipment,services and prices.Competitive in the transport industry usually drives the prices down and motivates for better services.A company also chooses its transport service provider because of its long-standing business relationship with certain shipping companies. 3.The alternative routing and scheduling is specific for motor only because railway and water have strict route and timetable.Motor has special advantage in terms of flexibility.It has the ability to load goods at greater frequency,travel through different routes and making deliveries to different loca-tions.Questions:

How is a transportation service provider selected？（）

A.By supplier.

B.Referral.

C.Customer demands.

D.Experiences and equipments.
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