Expensive perfumes (香水) come in tiny bottles, but many hide a whale-sized secret.

To perfect a particular smell, perfume-makers often use an ingredient that comes from

sperm whales, called ambergris (龙涎香). But using ambergris, which helps a perfume last

longer, is strongly opposed by many people who think it is wrong to kill whales just so we can

smell sweet. Joerg Bohlmann is neither a perfumer nor a whale expert. He's a plant biologist at

the University of British Columbia in Canada. But his discovery of a new plant gene (基因)

might push whales out of the perfume business.

The gene comes from fir trees, found throughout North America and commonly used as

Christmas trees. The trees produce a chemical that can be used in perfume in place of

ambergris-but with a catch. "There's a problem that many people wouldn't consider. In the

tree, the chemical is mixed with many others. That makes separation a challenge," Bohlmann

says. "lt's like trying to isolate sugar from a biscuit. "

This is where science becomes useful. When Bohlmann learned that fir trees produce the

ambergris-like chemical, he decided to use his gene know-how to find the instructions for how

to make the ambergris-substitute.

Bohlmann found that gene and took it out of the tree cells. Then he did something that

might sound strange to someone who doesn't work in genetics: Bohlmann put the gene from the

tree into yeast (酵母) cells.

Yeast may sound familiar because it's used to make things like bread, wine and beer.

Biologists like to work with yeast because it easily adopts new genes and changes its features

and behaviour. When Bohlmann put the fir tree gene into the yeast, the yeast started making

the same chemical that had been produced by the tree.

Perfumers pay big money for ambergris because it is a fixative, which means it holds a

smell in place on a person's body.

"Cheap perfumes smell good in the first hour or so and then everything is gone," explains

Bohlmann. "But expensive perfumes are much more stable. Their smell lasts much longer, for

hours or even a day after you apply them. "

The new chemical, made from the tree genes, can be used as a fixative, too. And using

yeast to make it is far cheaper than acquiring ambergris.

Bohlmann admits he never thought he'd get into the perfume business. But now, he says,

producers have been calling to find out how to use his technology in new perfumes.

32. It can be inferred from the passage that if a perfume contains ambergris, .

A. its user probably supports whale hunting

B. its smell will last for about an hour

C. it is probably very expensive

D. there will be a whale symbol on the bottle

33. The underlined expression "with a catch" in Paragraph 3 means____.

A. being difficult to hold B.being too similar

C. needing further testing D. having a hidden problem

34. According to the passage, why are yeast cells often used in genetic research?

A. They're much cheaper to use than ambergris.

B. They can reproduce much faster than other cells.

C. They share some of the qualities of plant genes.

D. They can take on the characteristics of other genes.

35. What can we learn about Joerg Bohlmann from the passage?

A. He has previously done genetic research.

B. He made his discovery during Christmas.

C. He has worked in the perfume industry for many years.

D. He is opposed to whale hunting. 高考英语模拟试题库  http://www.17xuexiba.com/yy/