预作用系统报警阀组压力表读数不在正常范围内的原因可能是（）。 A.预作用装置前的供水

目前常用的交换式以太局域网，其数据传输速率通常为

A．1Mbps

B．10Mbps

C．10．100Mbps

D．56Kbps

When prehistoric man arrived in new parts of the world, something strong happened to the large animals; they suddenly became extinct. Smaller species survived; the large, slow-growing animals were easy game, and were quickly hunted to extinction. 

Now something similar could be happening in the oceans. That the seas are being over-fished has been known for years and researchers such as Ransom Myers and Boris Worm have shown how fast things are changing. They have looked at half a century of data from fisheries around the world. Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time. According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) inanes fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then.

Dr. Worm acknowledges that these figures are conservative (保守的). One reason for this is that fishing technology has improved. Today’s vessels can find their prey using satellites and sonar, which were not available 50 years ago. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes. In the early days, too, longlines would have been more saturated with fish. Some individuals would therefore not have been caught, since baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past. Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around noise.

Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. They believe the date support an idea current among marine biologists, that of the “shifting baseline”. The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past. That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels. Most fisheries are well below that, which is a bad way to do business.

小题1:The aim of the extinction of large prehistoric animals is to suggest that _______.

A．large animal were not easy to survive in the changing environment

B．small species survived as large animals disappeared

C．large sea animals may face the same threat today.

D．Slow-growing fish outlive fast-growing ones小题2:We can infer from Dr Myers and Dr. Worm’s paper that _______.

A．the stock of large predators in some old fisheries has reduced by 90%

B．there are only half as many fisheries are there were 15 years ago

C．the catch sizes in new fisheries are only 20% of the original amount

D．the number of larger predators dropped faster in new fisheries than in the old小题3:By saying these figures are conservative (line 1, paragraph 3), Dr worm means that_______.

A．fishing technology has improved rapidly

B．then catch-sizes are actually smaller then recorded

C．the marine biomass has suffered a greater loss

D．the date collected so far are out of date.小题4:Dr Myers and other researchers hold that _______.

A．people should look for a baseline that can’t work for a longer time

B．fisheries should keep the yield below 50% of the biomass

C．the ocean biomass should restore its original level.

D．people should adjust the fishing baseline to changing situation.小题5:The author seems to be mainly concerned with most fisheries’ _______.

A．management efficiency

B．biomass level

C．catch-size limits

D．technological application.

一般纳税人向小规模纳税人销售应税项目，也可以开具增值税专用发票。

针对“菲律宾国会通过法案将黄岩岛和南沙群岛部分岛礁划为菲律宾领土”一事，中国外交部发表声明指出，黄岩岛和南沙群岛历来都是中国领土的一部分，中华人民共和国对这些岛屿及其附近海域拥有无可争辩的主权。这说明（　）

A．领土是国家存在的最重要因素

B．主权完整是国家合作的基础

C．主权是国家的生命和灵魂

D．维护主权独立是我国外交政策的宗旨

不能打开HTML源码文件的软件为 （1) 。若在网页中需要增加“提交”和“重置”两个按钮，则应将它们的TYPE属性分别设置为 (2) 。在HTML的标记中，不需要成对出现的标记为 (3) 。

（1）处应填（）

A．Word

B．Notepad

C．HotJava

D．Adobe Reader