心理咨询的对象主要是（） A.病人 B.正常人 C.病人家属 D.正在恢复的病人 E

下列加点的字，注音不正确的一组是（  ）

A．荒芜(wú)宿(sù)舍玉砌(qì)雕栏

B．坍圮(pǐ)颓(tuí)墙亘(gèn)古不变

C．熨(yùn)贴灼(zhuō)烈声名狼藉(jí)

D．隽(juàn)永恪(kè)守猝(cù)然去世

输入电阻

* * B型超声最早在宫腔内见到妊娠囊的时间，是停经（）

A.6～7周

B.8～9周

C.10～11周

D.2～3周

E.4～5周

下表表示不同陆地生态系统的物质生产、分解的有关数据，请分析回答：

进一步调查得到某生态系统各营养级和分解者能量流动情况如下表

（其中E为分解者；Pg表示生物同化作用固定的总能量，Pn表示生物体贮存能量Pn=Pg－R，R表示生物呼吸消耗的能量）

该生态系统的营养结构可表示为（）；第二营养级到第三营养级的能量传递效率约为（）（保留整数）。

A Thirsty Planet

If you live in a city in North America or Europe, you have probably never thought much about water. Whenever you need some, you turn on the tap and there it is. Millions of people in other parts of the world are not so lucky. They have trouble getting enough clean water for their basic needs. This situation may soon become common all around the world, scientists believe. In fact, they say that the tack of clean water may be one of the biggest issues in the twenty-first century.
The reasons for this are clear. On the one hand, people are using more water than ever before. Over the last fifty years, the population of the world has more than doubled. So has the demand for water — for home use, for farming and for industry. On the other hand, supplies of clean water are disappearing. Many sources of surface water — such as rivers, lakes and streams — are too polluted and unhealthy for use as drinking water. This has forced more and more people to drill wells so they can get water from underground.
There are enormous amounts of water deep underground in lakes called aquifers. Until recently, scientists believed this groundwater was safe from pollution. Then, in 1980s, people in the Untied States began to find chemicals in their well water, and scientists took a closer look at what was happening. Weldon Spring, Missouri, for example, was the site of a bomb factory during World War Ⅱ. The factory was destroyed after the war, but poisonous chemicals remained on the ground. Very slowly, theses chemicals dripped down through the ground and into the aquifer. Once they did, however, the water from that aquifer was no longer drinkable.
It probably never will be drinkable again. Groundwater is not renewed regularly by the rain, like lake or river water. Thus, if a harmful chemical gets into an aquifer, it will stay there for a very long time. Furthermore, it is nearly impossible to remove all the water in an aquifer and clean out the pollutants.
Industrial sites like Weldon Spring are one cause of groundwater pollution. There are thousands of such sites in the Untied States alone, and many others around the world. Groundwater pollution is also caused by modem farming methods, which require the use of large amounts of chemicals in the fields. And finally, yet another important cause of groundwater pollution is waste. That includes solid waste thrown away in dumps and landfills, and also untreated human and animal waste.
The situation is indeed very serious. Fortunately, there are many aquifers and they are very large. Only a small number have been seriously damaged so far. But if the world does not want to go thirsty in the near future, further pollution must be prevented. Around the world, governments must make real changes in industry, agriculture and waste disposal.

If chemicals get into groundwater, ______.
A. it is not good to drink
B. people can drink it anyway
C. they can be removed
D. they will be washed away