[单项选择]

At some time around 2300BC, give or take a century or two, a large number of the major civilizations of the world collapsed, in Mesopotamia, Egypt, Israel, Anatolia, and Greece, as well as in Afghanistan and China. All of them the first urban civilizations fell into rain at more or less the same time. A thousand years later, around 1200BC, many of the civilizations of the same regions again collapsed at about the same time.
The reasons for these widespread and apparently simultaneous disasters which coincided with changes to cultures and societies elsewhere, such as in Britain, have long been a fascinating mystery. Traditional explanations included warfare, famine, and more recently systems collapse, but the apparent absence of direct archaeological or written evidence for causes, as opposed to effects, has led many archaeologists and historians into a resigned assumption that no definite explanation can be found.
Over the past 15 years, however, a new type of &rs
A. the destruction at the sites had been severe.
B. the sites had not been destroyed by war.
C. there was no evidence of humans causing the disasters.
D. all of the above.

At some time around 2300BC, give or take a century or two, a large number of the major civilizations of the world collapsed, in Mesopotamia, Egypt, Israel, Anatolia, and Greece, as well as in Afghanistan and China. All of them the first urban civilizations fell into rain at more or less the same time. A thousand years later, around 1200BC, many of the civilizations of the same regions again collapsed at about the same time.
The reasons for these widespread and apparently simultaneous disasters which coincided with changes to cultures and societies elsewhere, such as in Britain, have long been a fascinating mystery. Traditional explanations included warfare, famine, and more recently systems collapse, but the apparent absence of direct archaeological or written evidence for causes, as opposed to effects, has led many archaeologists and historians into a resigned assumption that no definite explanation can be found.
Over the past 15 years, however, a new type of &rs
A. it occurred simultaneously.
B. it occurred at a time similar to noticeable cultural and social changes
C. there are no written records.
D. all of the above.

Some people give up trying to learn a foreign language. It can seem too much like hard work. But the problem comes when they go abroad on holidays and find they cannot communicate. How do they ask the way, order a cup of coffee, or ask the price of something
Keith Chiwick thinks he has the answer to this problem. "I have got a machine which talks in different languages. I feel that I could go to any country in the world and converse with any foreigner," he says. Keith is an inventor. His invention is an electronic machine which produces phrases in four different languages, French, German, Italian and English. Unlike the phrase books, this machine has a voice. It looks like a cassette recorder.
Imagine you want to say, "What time is the next train for Munich" in German. First, you find the right card for that question. Each card has four strips of tape on it, one for each language. The cards are small, seven by nine centimeters, and each one can
A. Because they can use Keith’ s machine now.
B. Because it is like hard work.
C. Because they have difficulties to go abroad.
D. Because they cannot communicate with foreigners.