问题 填空题

氢气球下吊一小石块匀速上升,则小石块受到______力的作用.若吊石块的绳子断了,则小石块在落地前的运动变化情况是______.

答案

因为氢气球和小石块匀速上升,因此小石块受平衡力作用;若吊石块的绳子断了,小石块由于惯性还要保持原来的运动状态向上运动;又因为受重力的作用,小石块上升一段距离后,速度为零,然后向下运动.

故答案为:平衡;先上升后下降.

填空题

填空:阅读下面短文,根据所读内容在文后第76至第85小题的空格里填上适当的单词或短语。

注意:每空不超过3个单词。

     What is eco-fashion? Eco-fashion is a complex phenomenon and the common use of the term covers

two aspects of fashion-'ecological' and 'ethical' (伦理的). Ecological fashion usually refers to textile (织

物) and clothing production processes and the environmental issues (议题) surrounding them; ethical

fashion generally relates to the working conditions involved in the producing processes.

     What are the problems with fashion? Firstly, the production of textiles pollutes the environment heavily.

Cotton-planting uses pesticides; sheep-farming and wool-cleaning contribute to global warming; synthetics-

making (人造纤维生产) brings about harmful waste. Secondly, every stage of clothing production has a

significant effect on the environment. They all use a great deal of energy, and some also involve harmful

chemicals. In addition to this, there is a lot of waste produced in the process, especially in the form of

polluted water. Thirdly, growing consumption levels and our shopping habits further worsen the bad effects.

We are now buying clothes in increasing quantities without realizing the scale on which it affects natural

environment, and we are also quick to throw away clothes that have been worn only a couple of times.

     Then, how to solve the problems? To a large degree, it is the fashion producers that really have the power

and the responsibility to shape our future. There are numerous ways in which these producers can reduce

their ecological footprint, from switching to green energy and reducing energy use, through selecting

sustainable (可持续使用的) materials and choosing local suppliers, to recycle and minimize waste. On the

other hand, as consumers we can all make contributions by selecting environmentally friendly clothing and

reducing clothing consumption.

     Now many people are beginning to shop for organic food products because the benefits of eating food

free of chemicals are straightforward and immediate. They relate directly to our personal health. In fact,

choosing eco-fashion can also contribute to our personal health, though it is mostly done by way of keeping

the health of the planet.

问答题 简答题