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问题 选择题

关于摩擦力的说法，以下错误的是（　　）

A．相对运动的物体间一定有摩擦力

B．摩擦力的大小跟压力成正比

C．滑动摩擦力的方向总是沿着接触面，并且跟物体的运动方向相反

D．静摩擦力的方向总是沿着接触面，并且跟物体相对运动趋势方向相反

答案

A、相对运动的物体间要有摩擦力，接触面必须粗糙，而且要相互挤压．所以相对运动的物体间不一定有摩擦力．故A错误．

    B、滑动摩擦力与正压力成正比，而静摩擦力与压力没有必然的关系．故B错误．

    C、滑动摩擦力的方向总是沿着接触面，可以跟物体的运动方向相反，也可以跟物体的运动方向相同，但一定与物体的运动相对方向相反．故C错误．

    D、静摩擦力的方向总是沿着接触面，并且跟物体相对运动趋势方向相反．故D正确．

本题选错误的，故选ABC

选择题

细胞中有很多物质，下面列举的各组物质全部是有机物的是（　　）

A．无机盐、脂类、蛋白质、糖类

B．水、无机盐、脂类、糖类

C．糖类、脂类、蛋白质、核酸

D．无机盐、氧、脂类、蛋白质
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单项选择题

Questions from 31 to 35 are based on the following passage: Negotiations work wonders. This is particularly so in international business since it is mostly through negotiations that exporters and importers bridge their differences and reach a fair and mutually satisfactory deal. By presenting a more comprehensive negotiating package in a well planned and organized manner, exporters should be able to improve the effectiveness of their business discussions and in the long term the profitability of their export operations. To avoid being confronted by costly demands, an exporter should try to determine the buyer’s real interest in the products from the outset. This can be ascertained through appropriate questions but must also be based on research and other preparations before the negotiations. Only then can a suitable counter-proposal be presented. To achieve a favorable outcome from the negotiations, an exporter should draw up a plan of action beforehand, which addresses a few key issues. Experienced negotiators consider that as much as 80% of their overall time devoted to negotiations should go to such preparations. The preliminary work should be aimed at obtaining relevant information on the target market and the buyers of the products. It should also include developing counter-proposals if objections are raised on any of the exporter’s opening negotiating points. The preparations should thus involve formulating the negotiating strategy and tactics.In international marketing negotiations, it is advisable for small and medium-sized exporters not just to limit their discussions to pricing issues, although pricing is a key factor in any business transaction, exporters should give more attention to the full range of marketing factors. They should stress the strengths of their firms and products and match them with the perceived needs of the buyers. Once these issues have been covered, they can consider the question of price and are able to develop a profitable business.

The author advises the small and medium-sized exporters to do business with（）.

A．care

B．a prospective insight

C．more stress on profit

D．pricing issues
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