You have seen Helen in her office this mornin...

You 　　　　 have seen Helen in her office this morning because she’s been out of town for two weeks.

A. needn’t　　　　　 B. mustn’t

C. mightn’t　　　　　 D. couldn’t

高二英语单项填空中等难度题查看答案及解析

You _______ her in her office last Friday; she’s been out of town for two weeks.

A. needn’t have seen   B. must have seen   C. shouldn’t have seen    D. can’t have seen

高二英语单项填空简单题查看答案及解析

--- Why were you so late for work today？

--- ________ to the office was very slow this morning because of the traffic.

高二英语单项填空中等难度题查看答案及解析

----Have you seen _____ pen? I left it here this morning.

----Is it ____ black one? I think I saw it somewhere.

高二英语单项填空困难题查看答案及解析

—Have you seen _________ watch? I left it here this morning.

—I think I saw one somewhere. Is it _________ new one?

A. a；/ 　        B. a；the　        C. the；a 　        D. a；a

高二英语单项填空简单题查看答案及解析

----Have you seen＿＿＿＿pen﹖I left it here this morning.

-----Is it＿＿＿＿black one﹖I think I saw it somewhere.

A．a；the         B．the；the        C．the；a         D．a；a

高二英语单项填空中等难度题查看答案及解析

-Have you seen_____pen？I left it here this morning.

-ls it_____ black one？I think I saw it somewhere.

A. a，the B. the，the

C. the，a D. a，a

高二英语单项填空困难题查看答案及解析

-- Have you seen ______pen? I left it here this  morning

-- Is it ______black one? I think I saw it somewhere

A．a；the            B．the；the          C．a；a             D．the；a

高二英语单项填空中等难度题查看答案及解析

---This is the first time that I have seen you in this neighbourhood!

--- I ________ here only last week.

A．moved           B．move             C．had moved        D．am moving

高二英语单项填空中等难度题查看答案及解析

Have you seen Jurassic Park? In this film, scientists use DNA kept for tens of millions of years to clone dinosaurs. They find trouble, however, when they realize that the cloned creatures are smarter and more dangerous than expected. That’s nothing more than a fiction.

But could we really clone endangered animals?

To date, the most successful attempt to do so was the cloning of a gaur, a rare ox-like animal from southeast Asia. Scientists used a cow to bring the cloned baby gaur, named Noah. Two days after birth, however, Noah died from a common bacterial infection. Other endangered species that may be cloned include the African bongo antelope (羚羊), the Sumatran tiger, the cheetah (猎豹), and the giant panda.

Next, could we really clone extinct animals?

In theory? Yes. To do this, you need a well-kept source of DNA from the extinct animals such as wool mammoth (毛象), Tasmanian tiger, or even dinosaur, and a closely related species, still living, which could serve as a surrogate mother.

In reality? Probably not. On the one hand, it’s not likely that extinct animals’ DNA could survive undamaged for such a long time. Cloning such extinct animals as wool mammoth, Tasmanian tiger, or dinosaur is much more difficult due to the lack of properly well-preserved DNA. On the other hand, for example, a gaur can have a cow as a surrogate mother, definitely not a monkey. But what about an extinct animal as unique as the panda? What species could possibly serve as a surrogate mother?

Cloning presents many exciting possibilities. However, even if extinct animals were brought back, they could not survive in today’s world. Not only do most extinct animals have no habitat to love in, but the other plants and animals they depended on for food may also be gone as well.

1. It can be learned from the text that ________.

A. the gaur is an extinct species

B. the gaur lives in Asia and is endangered

C. scientists have cloned the African bongo antelope

D. both the cheetah and the giant panda live in Asia

2.The underlined words “a surrogate mother” probably refer to a female who ______.

A. gives birth to a baby of its own                 B. cannot give birth to a baby

C. gives birth to a baby for another female             D. provides DNA

3.The difficulty in cloning an extinct species is the lack of ______.

A. both the well-preserved DNA and a surrogate mother

B. both the habitat to live in and the well-preserved DNA

C. both the well-preserved DNA and plants to live on

D. both the habitat to live in and plants to live on

4.In the author’s opinion, it is possible that ______.

A. all the extinct species may be cloned

B. extinct species may be cloned and easily survive

C. a gaur can have a monkey as a surrogate mother

D. some extinct species may be cloned, but not survive

高二英语阅读理解困难题查看答案及解析