Questions 36 to 40 are based on the following passage:
Why does cream go bad faster than butter? Some researchers think they have the answer, and it comes down to the structure of the food, not its chemical composition―a finding that could help rid some processed foods of chemical preservatives.
Cream and butter contain pretty much the same substances, so why cream should sour much faster has been a mystery. Both are emulsions―tiny globules (小球体) of one liquid evenly distributed throughout another. The difference lies in what’s in the globules and what’s in the surrounding liquid, says Brocklehurst, who led the investigation.
In cream, fatty globules drift about in a sea of water. In butter, globules of a watery solution are locked away in a sea of fat. The bacteria which make the food go bad prefer to live in the watery regions of the mixture. “This means that in cream, the bacteria are free to grow throughout the mixture,” he says.
When the situation is reversed, the bacteria are locked away in compartments (隔仓室) buried deep in the sea of fat. Trapped in this way, individual colonies cannot spread and rapidly run out of nutrients (养料). They also slowly poison themselves with their waste products. “In butter, you get a self-limiting system which stops the bacteria growing,” says Brocklehurst.
The researchers are already working with food companies keen to see if their products can be made resistant to bacterial attack through alterations to the food’s structure. Brocklehurst believes it will be possible to make the emulsions used in salad cream, for instance, more like that in butter. The key will be to do this while keeping the salad cream liquid and not turning it into a solid lump.
36. The significance of Brocklehurst’s research is that ____________.
A) it suggested a way to keep some foods fresh without preservatives
B) it discovered tiny globules in both cream and butter
C) it revealed the secret of how bacteria multiply in cream and butter
D) it found that cream and butter share the same chemical composition
37. According to the researchers, cream sours fast than butter because bacteria _________.
A) are more evenly distributed in cream
B) multiply more easily in cream than in butter
C) live on less fat in cream than in butter
D) produce less waste in cream than in butter
38. According to Brocklehurst, we can keep cream fresh by ___________.
A) removing its fat
B) killing the bacteria
C) reducing its water content
D) altering its structure
39. The word “colonies” (Line 2, Para. 4) refers to __________.
A) tiny globules
B) watery regions
C) bacteria communities
D) little compartments
40. Commercial application of the research finding will be possible if salad cream can be made resistant to bacterial attack _____________.
A) by varying its chemical composition
B) by turning it into a solid lump
C) while keeping its structure unchanged
D) while retaining its liquid form
36. 问B同学的研究的重要意义是什么？看第一段以问号提出问题，接着就给出了答案：归因于食物的结构。然后说：这一新发现可以帮助某些加工食品摆脱防腐剂。这就是研究的重要意义，所以答案是A。有的同学会不太肯定，因为问题中有问B同学，而第一段就没有提到B同学，只是说Some researchers。那么我们也可以先不选，接着往下看，就会发现B同学就是Some researchers中的一个，他的研究也归因于食物的结构。答案是A。
38.问通过什么手段来保鲜。在最后一段的第一句话。Alterations to the food’s structure。答案选D。而且文章第一段说：奶油比黄油坏得快归因于食物的结构。那么要保鲜让它坏得慢当然是要改变结构了。ABC都是文章中没有提到的内容。
39.指代题，要从所有格、单复数、位置、意义等方面向上找答案，因为它只会指代前面出现的内容。colonies是复数名词，前面出现的复数名词有the bacteria和compartments ，答案在CD里面。再看文中对应的这句话说：colonies不能展开，很快就耗尽养料。可以看出colonies指的是细菌。答案是C。