1 . Based on bone and tooth records, mammoths（猛犸象）were thought to have gone extinct about 12,000 years ago. But a new genetic sampling technique suggests the great beasts may have stuck around a lot longer. The story is in the soil.
Bones are rich sources of prehistoric genetic information, but not the only ones; items ranging from shed Ice Age skin cells to pine needles can contribute to the genetic record stored in dirt. Paleogeneticists（古遗传学家）have been analyzing "environmental DNA" from soil for a long time, but getting rid of non-DNA material without destroying these fragile clues is daunting（使人气馁的）.
"Environmental samples contain a huge range of other chemical substances that are hard to separate from the DNA," says McMaster University geneticist Tyler Murchie. "We can't afford to lose whatever we can get."
In the new approach, soil samples are got and then broken into smaller portions, stirred and run through a "cold spin method" to separate as much DNA as possible. The DNA is then compared against an existing genetic library to detect species matches.
The method is limited because researchers using it need to know what DNA to look for. If a saber-toothed cat species is not already in the genetic library, the analysis cannot detect that animal. For known species, however, the process may yield exciting information. In their study, the researchers detected about 2,100 kinds of plants and 180 animals.
Not yet published results from other field sites are yielding similar results, Murchie says, and future fossil discoveries could strengthen the case. "We can use this approach to identify species in places and times we never knew they existed," he adds.
1. Why does the author mention "mammoths" in Paragraph 1?| A．To present a fact. | B．To show us an extinct animal. |
| C．To correct a mistake. | D．To introduce the topic of the passage. |
| A．Challenging. | B．Interesting. |
| C．Boring. | D．Satisfying. |
| A．It is very slow. |
| B．It can't detect unknown animals. |
| C．It is not very accurate. |
| D．It can only be carried out in the genetic library. |
| A．A news report. | B．A short story. |
| C．A book review. | D．A research report. |
增加:在缺词处加一个漏字符号( ˄), 并在其下面写出该加的词。
删除:把多余的词用斜线(\)划掉。
修改:在错的词下划一横线, 并在该词下面写出修改后的词。
注意:1.每处错误及其修改均仅限- - -词;
2.只允许修改10处, 多者(从第11处起)不计分。
Liu Chuanjian, a pilot for Sichuan Airlines Flight 3U8633, has been given the honorary title of “CAAC Heroic Captain” and the award of 5 million yuan at a meeting holding by the Civil Aviation Administration of China and Sichuan provincial government on Friday. As he flies the Airbus A319 over Chengdu on May 14, 2018, the right-hand side of the windscreen broke. Unfortunately, her co-pilot was near sucked out. Liu had landed the plane at the Chengdu Airport, and all crew members and the 119 passenger were saved. On the meeting, the crew of Flight 3U8633 was honored as the “CAAC Heroic Crew”. The second captain Liang Peng awarded 2 million yuan and the co-pilot 1 million yuan, with the other six crew members shared 1 million yuan.
Different kinds of birds build different kinds of nests. Birds build nests in all sorts of places, from on the ground to high up in trees and on the sides of mountains. Some birds make nests
The reason birds make nests is to have a
Most birds nest during the spring and early summer of each year. They raise their babies in quite a short time. They lay the eggs, and then keep them warm for three to four weeks. After they hatch, many young birds learn to fly in
4 . I had been practising my speech for days, but I was still stressed out. I was in the first year of my PhD, and my
When my turn to speak finally came, I focused on
I continued to view my.
Instead of trying to
My efforts rapidly
| A．unique | B．previous | C．special. | D．later |
| A．whisper | B．battle | C．rush | D．way |
| A．firm | B．rough | C．shocking | D．shaking |
| A．impression | B．assistance | C．truth | D．preference |
| A．incidents | B．loss | C．adjustments | D．attention |
| A．audience | B．techniques | C．time | D．contents |
| A．used | B．planned | C．expected | D．forgotten |
| A．afraid. | B．tired | C．proud | D．ashamed |
| A．evidence | B．idea | C．desire | D．option |
| A．efforts | B．discoveries | C．experiences | D．talks |
| A．suggestions | B．excitement | C．approval | D．questions |
| A．record | B．convey | C．oppose | D．obtain |
| A．disappointing | B．frightening | C．wonderful | D．traditional |
| A．delighted | B．satisfied | C．connected | D．bored |
| A．help | B．fill | C．refresh | D．strike |
| A．ignored | B．wrote | C．refused | D．sought |
| A．practiced | B．copied | C．criticized | D．corrected |
| A．went on | B．paid off | C．ended up. | D．got around |
| A．tiredness | B．reputation | C．curiosity | D．confidence |
| A．tips | B．reasons | C．followers | D．cheers |
1. Where is the new museum situated?
| A．On Liberty Island. | B．On Ellis Island. | C．In the City of New York. |
| A．In 1954. | B．In 1892. | C．In 1886. |
| A．About 900, 000. | B．About 500, 000. | C．About 400, 000. |
| A．The statue of the creator of Lady Liberty. |
| B．The inside structure of Lady Liberty. |
| C．The constructing process of Lady Liberty. |
1. Who is going to have dinner with the woman?
| A．David. | B．Paul. | C．Jane. |
| A．His client is difficult to please. | B．He has no time to keep a date. | C．The printer doesn't work. |
| A．It is easy to handle. | B．It is demanding. | C．It doesn't make sense. |
| A．Get changed. | B．Call for a technician. | C．Ring her husband. |
1. Where does the conversation probably take place?
| A．At home. | B．In an office. | C．In a restaurant. |
| A．About two years ago. | B．About three years ago. | C．About four years ago. |
| A．He taught English. | B．He worked in a company. | C．He continued with his study. |
1. What can we know about the man?
| A．He is not a local resident here. |
| B．He often ignores the traffic rules. |
| C．He doesn't know the woman at all. |
| A．Tour around the city. | B．Buy something to drink. | C．Park her car somewhere. |
1. What does the woman complain about?
| A．Boring travel plans. | B．Hot weather. | C．Short summer holidays. |
| A．It will cool down over the weekend. |
| B．The weather forecast is not accurate. |
| C．Going to the pool is a good idea. |
| A．Friends. | B．Teacher and student. | C．Driver and passenger. |
