Even ancient Egypts mighty pyramidbuilders were powerless in the face of the faminethat helped bring down their civilization around 2180 B.C..Now evidence collected from mud deposited by the River Nile suggests that a shift in climate thousands of kilometers to the south was ultimately to blame--and the same or worse could happen today.
The ancient Egyptians depended on the Niles annual floods to irrigate their crops.But any change in climate that pushed the African monsoonssouthwards out of Ethiopia would have reduced these floods.
Declining rains in the Ethiopian highlands would have meant fewer plants to stabilize the soil.W.1len rain did fall it would have washed large amounts of soil into the Blue Nile and into Egypt，along with sedimentfrom the White Nile.
Blue Nile mud has a different isotopesignature from that of the white Nile.So by analyzing isotope differences in mud deposited in the Nile Delta.Michael Krom of LeedsUniversity worked out what proportion of sediment came from each branch of the river.
Krom reasons that during periods of drought，the amount of Blue Nile mud in the river would be relatively high.He found that one of these periods，from 4500 to 4200 years ago。immediately came before the fall of the Egypts old Kingdom.
The weakened waters would have been disaster for the Egyptians.Changes that affect food supply dont have to be very large to have a rippleeffect in societies，says Bill Ryan of the Lamont Doherty Earth Observatory in New York.
Similar events today could be even more devastating，says team member Daniel Stanley.ascientist from the Smithsonian Institution in Washington D.C.Anything humans do to shift the climate belts would have an even worse effect along the Nile system today because the populations have increased dramatically.
36 Why does the author mention Egypts mighty pyramid builders?
A Because they once worked miracles.
B Because they were wellbuilt.
C Because they were actually very weak.
D Because even they were unable to rescue their civilization.
37 Which of the following factors was ultimately responsible for bringing down the civilization of ancient Egypt?
A Change of climate.
B Corrulption.
C flood.
D Population growth.
38 which of the following statements is true?
A The White Nile is the trunk of the River Nile.
B The White Nile is the trunk of the Blue Nile.
C The White Nile is a branch of the Blue Nile.
D The White Nile is a branch of the River Nile.
39 According to Krom，the Egypts o1d Kingdom fell
A immediately after a period of drought.
B immediately after a period of flood.
C just before a drought struck.
D just before a flood struck.
40 The word devastating in the last paragraph could be best replaced by
A frustrating.
B damaging.
C defeating.
D worrying.
答案解析
36.D这道题问的是：作者为什么提及古埃及伟大的金字塔建筑者?文章开头有这么一句话，中文意思是：即使古埃及伟大的金字塔建筑者面对那场在公元前2180年促使他们的文明毁灭的饥荒也无能为力。D说的是：即使是他们也不能挽救他们的文明。因此D是正确的答案。A说的是：他们曾创造过奇迹。B说的是：他们很强壮。C说的是：他们其实很弱。
37.A这道题问的是：下面列出的几种因素中哪一种因素是造成古埃及文明毁灭的根本性因素。A说的是：气候变化。第一段中有这样一个子句：a shift in climatewas ultimately to blame最终归咎于气候的变化。在第一题的题解中，我们提到了饥荒 与古埃及文明毁灭的关系。但饥荒是表层的因素，气候的变化才是古埃及文明毁灭的深层的因素。因此，A是正确的答案。B：腐败。c：水灾。D：人口增长。
38.D这道题问的是：下面列出的几种陈述哪一种是正确的?D说的是：白尼罗河是尼罗河的支流。第四段中的最后一句话是这么说的：worked out whatproportion of sediment came from each branch ofthe river.找到了来自河的每条支流的沉积物的比例。这里的河是指尼罗河，每条支流回指上文所说的青尼罗河和白尼罗河。因此，D 是正确的答案。A：白尼罗河是尼罗河的干流。B：白尼罗河是青尼罗河的干流。c：白尼罗河是青尼罗河的支流：显然，这些都不构成答案。
39.A这道题问的是：古埃及王朝毁灭发生在什么时候?A说的是：就在一个时期的干旱之后。第五段有这么一个句子：one of these periodsimmediately came before the fall of the Egypts Old Kingdom.其中的一个时期就发生在古埃及王国毁灭之前。可以看出，A应该是正确的答案。B：就在一个时期的水灾之后。C：就在遇到一次旱灾之前。D：就在遇到一次水灾之前。
40.B devastate是及物动词。意思是：使荒芜;破坏。devastating既是现在分词，又是形容词。此处devastating不是现在分词，因为它后面不跟名词短语，它只能是形容词。它的意思是：破坏性的。frustrate是动词。意思是：使受挫;受挫。frustrating是现在分词，同时也是形容词。作形容词时，它的意思是：失望的。可以看出，它跟devastating的意思相差很远。damage：破坏，毁灭。damaging是它的现在分词，但它本身也是形容词，意思是：破坏的或毁灭的。跟devastating意思相近，是合适的选择。defeat：击败。worry：担忧，发愁。worrying：令人担忧的，令人发愁的。