[填空题]Until about two million years ago, Africa’s vegetation had always been controlled by the interactions of climate; geology, soil, and groundwater conditions; and the activities of animals. The addition of humans to the latter group, however, has increasingly rendered unreal the concept of a fully developed "natural" vegetation—i.e., one approximating the ideal of a vegetational climax.
(16)
Early attempts at mapping and classifying Africa’s vegetation stressed this relationship. sometimes the names of plant zones were derived directly from climates. In this discussion the idea of zones is retained only in a broad descriptive sense.
(17)
In addition, over time more floral regions of varying shape and size have been recognized. Many schemes have arisen successively, all of which have had to take views on two important aspects, the general scale of treatment to be adopted, and the degree to which human modification is to be comprehended or

[填空题]Until about two million years ago, Africa’s vegetation had always been controlled by the interactions of climate; geology, soil, and groundwater conditions; and the activities of animals. The addition of humans to the latter group, however, has increasingly rendered unreal the concept of a fully developed "natural" vegetation—i.e., one approximating the ideal of a vegetational climax.
(16)
Early attempts at mapping and classifying Africa’s vegetation stressed this relationship. sometimes the names of plant zones were derived directly from climates. In this discussion the idea of zones is retained only in a broad descriptive sense.
(17)
In addition, over time more floral regions of varying shape and size have been recognized. Many schemes have arisen successively, all of which have had to take views on two important aspects, the general scale of treatment to be adopted, and the degree to which human modification is to be comprehended or

[填空题]

Until about two million years ago Africa’s vegetation had always been controlled by the interactions of climate; geology, soil, and groundwater conditions; and the activities of animals. The addition of humans to the latter group, however, has increasingly rendered unreal the concept of a fully developed "natural" vegetation-- i. e. , one approximating the ideal of a vegetational climax. (41) _____________________. Early attempts at mapping and classifying Africa’s vegetation stressed this relationship: sometimes the names of plant zones were derived directly from climates. In this discussion the idea of zones is retained only in a broad descriptive sense.

(42) _____________________. In addition, over time more floral regions of varying shape and size have been recognized. Many schemes have arisen successively, all of which have had to take views on two important aspects: the general scale of treatment to be adopted, and the degree to which human

[单项选择]

Passage Three Until two years ago, Clearing, Illinois was a tranquil suburb of Chicago. But residents grew alarmed when they noticed armed teenagers on the streets, giving gang signals and shouting at passing cars. Then came a series of burglaries and graffiti messages on store- fronts. By the time local authorities realized they had a gang problem, it was too late. Last December, two 13-year-old girls were shot outside their school as they sat in a car with two members of a local gang, the Ridgeway Lords. Nearly all 50 states have recently passed laws that allow youths aged 14-17 to be tried in court as adults. In about 25 states they have passed laws to punish parents for their children’s behavior. And in 146 of the nation’s largest cities, they have imposed curfews to reduce juvenile violence. When you look at the spectacular rise of violent crime among young people recently, it’s easy to understand the concern. Over the past decade, there ha
A. A famous band.
B. A gang.
C. A prison.
D. A unit.

[单项选择]Not until three years ago ______ to work outside.
A. he began
B. he begins
C. began he
D. did he begin

[单项选择]About four years ago, Kerry Sturgill found herself at a career crossroads: Should she stay in an industry populated by extroverts(外向型的人) or jump ship to a more reflective place where introverts like her were in the majority
Career counselors had told her to get out of the highly extroverted public relations fields " so you can be happy and do what you are. " Among the less fast-paced areas they pointed to: art, scientific research, data analysis.
Such a move is definitely the right road for many introverts struggling to fit into an extroverted workplace.
So, just what is an introvert anyway It’s someone who is energized by thought and reflection, while extroverts are energized by socializing. Introverts naturally need to think before they speak. Extroverts use the speaking process to figure out what it is they want to say.
And, needless to say, there are pluses and minuses to both personality types.
Still, in the modern world where as many as two-thirds of the
A. introverts should try to avoid working in a highly extroverted environment
B. introverts should try to change themselves to fit into an extroverted working environment
C. extroverts should work in less fast-paced areas such as art and scientific research
D. introverts can be happier if they can find jobs in the field of public relations

[单项选择]

About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course: The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen.
The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoo
A. The results of two experiments are compared.
B. A generalization is made, and several examples of it are given.
C. The findings of an experiment are explained.
D. A hypothesis is presented, and several means of proving it are suggested.