C
Imagine that the genome(基因组)is a book.The book consists of 23 chapters with housands of stories made up of paragraphs,words and letters on different levels. There are one billion words in the book,which makes it longer than 5 000 volumes the size of this book,or as long as 800 Bibles.If I read the genome out to you at the rate of one word per second for eight hours a day,it would take me a cent ury.If I wrote out the human genome,one letter per millimeter,my text would be a s long the River Danube.This is an enormous document,a huge volume,a cook book o f great leghth,and it all fits inside the extremely small nucleus(核) of a tiny cell that fits easily upon the head of a pin.
The idea of the genome as a book is not,strictly speaking,even a metaphor(比喻). It is true to a great extent.A book is a piece of digital information,written in one-directional form and defined by a code that translates a small alphabet of signs into a large dictionary of meanings through the order of their groupings.S ois a genome.The only complication is that all English books read from left to r ight while some parts of the genome read from left to right,and some from right to left,though never both at the same time.
While English books are written in words of different lengths using twenty-six l etters,genomes are written gntirely in three-letter words,using only four letter s.And instead of being written on flat pages,they are written on long chains of DNA molecules(分子).The genome is a very clever book,because in the right condit ions it can both photocopy itself and read itself.
9.How do human genomes read according to the passage?
A.Only from left to right.
B.Only from right to left.
C.From both directions at the same time.
D.From one direction at a time.
10.We can learn from the passage that the human genome( )
A.is as long as the River Danube
B.can be easily placed on the head of a pin
C.is coded with an alphabet of four letters
D.is smart enough to read and take photos of itself
11.It can be concluded that the passage is mainly written for( )
A.specialists in the field
B.general readers
C.natural scientists
D.readers with academic background
12.The real purpose of the author’s comparison of the genome to a book is ( ).
A.to focus on the differences between the two
B.to lay emphasis on the similarities between the two
C.to simplify the concept of the human genome
D.to give an exact description of the human genome
D
LET YOUR LOVE FOR ANIMALS LIVE ON
As some one who loves animals,you care about what will happen to them in the fut ure.CSIA has been treating sick and injured animals since 1938.It’s hard to imag ine what would happen to the hundreds of thousands f pets who need us every year if we to no longer existed.
But in fact we simply couldn’t continue if it wasn’t for a very special kind of gift people like you leave to us in their wills(遗嘱).
Can we depend on your kindness too?If you haven’t already done s o,please consider including a gift to CSIA in your will.For free information on how to go about it,please call our helpline on 0800 8421950.Your love for animal s can live on with a gift in your will to CSIS