We all have offensive breath at one time or another. In most cases, offensive breath emanates from bacteria in the mouth, although there are other, more surprising causes. Until a few years ago, the most doctors could do was to counsel patients with bad breath about oral cleanliness. Now they are finding new ways to treat the usually curable condition.
Bad breath can happen whenever the normal flow of saliva slows. Our mouths are full of bacteria feeding on protein in bits of food and shed tissue. The bacteria emit evil-smelling gases, the rest of which is hydrogen sulfide. Mouth bacteria thrive in airless conditions. Oxygen-rich saliva keeps their numbers down. When we sleep, for example, the saliva stream slows, and sulfur-producing bacteria gain the upper hand, producing classic “morning breath”. Alcohol, hunger, too much talking, breathing through the mouth during exercise — anything that dries the mouth produces bad breath. So can stress, though it’s not understood why. Some people’s breath turns sour every time they go on a job interview. Saliva flow gradually slows with age, which explains why the elderly have more bad-breath trouble than younger people do. Babies, however, who make plenty of saliva and whose mouths contain relatively few bacteria have characteristically sweet breath.
For most of us, the simple, dry-mouth variety of a bad breath is easily cured. Eating or drinking starts saliva and sweeps away many of the bacteria. Breakfast often stops morning breath. Those with chronic dry mouth find that it helps to keep gum, hard candy, or a bottle of water or juice around. Brushing the teeth wipes out dry-mouth bad breath because it clears away many of the offending bacteria.
Surprisingly, one thing that rarely works is mouthwash. The liquid can mask bad-breath odor with its own smell, but the effect lasts no more than an hour. Some mouthwashes claim to kill the bacteria responsible for bad breath. The trouble is, they don’t necessarily reach all offending germs. Most bacteria are well protected from mouthwash under thick layers of mucus. If the mouthwash contains alcohol — as most do — it can intensify the problem by drying out the mouth.
36. The phrase “emanate from” in Paragraph 1 most probably means “______”.
37. Which of the following is mentioned as one of the causes of bad breath?
38. According to the passage, alcohol has something to do with bad breath mainly because ______.
39. Mouth washes are not an effective cure for bad breath mainly because ______.
40. We can infer from this passage that ______.
问题1选项
A.thrive on
B.account for
C.originate from
D.descend from
问题2选项
A.Tooth trouble
B.Sulfur-rich food
C.Too much exercise
D.Mental strain
问题3选项
A.it keeps offending bacteria from reproducing
B.its smell adds to bad death
C.it kills some helpful bacteria
D.it affects the normal flow of saliva
问题4选项
A.they can’t mask the bad odor long enough
B.they can’t get to all the offending bacteria
C.their strong smell mixes with bad breath and makes it worse
D.they can’t cover the thick layers of mucus
问题5选项
A.offensive breath can’t easily be cured
B.elderly people are less offended by bad breath
C.heavy drinkers are less affected by bad breath
D.offensive breath is less affected by alcohol
第1题:C
第2题:D
第3题:D
第4题:B
第5题:A
36.【试题答案】C
【试题解析】语义推测题。题干意思是“第一段中的emanate from最可能的意思是……”。定位到第一段第二句In most cases, offensive breath emanates from bacteria in the mouth, although there are other, more surprising causes.（在大多数情况下，令人不快的口气emanates from口腔中的细菌，尽管还有其他更令人惊讶的原因），根据后面的causes可知，offensive breath 和bacteria in the mouth之间应该是一个因果关系，是bacteria 导致了offensive breath，那么可以反推，offensive breath是来源于bacteria ，故C项“发源于”正确。A项“以……成长”、B项“解释”和D项“由……传下来的”都不符合。因此，该题选择C项。
37.【试题答案】D
【试题解析】事实细节题。题干意思是“下列哪项被认为是造成口臭的原因之一？”。定位第一段第二句In most cases, offensive breath emanates from bacteria in the mouth（在大多数情况下，令人不快的口气来自口腔中的细菌）可知，口臭来自于口腔中的细菌，而细菌通常容易造成牙齿问题，所以A项“牙齿问题”是口臭的一个原因。定位第二段第六句When we sleep, for example, the saliva stream slows, and sulfur-producing bacteria gain the upper hand, producing classic “morning breath”.（例如，当我们睡觉时，唾液流得很慢，产生硫的细菌占了上风，产生了所谓的“早晨口气”）可知，含硫的细菌能够导致口臭，所以B项“高硫的食物”是原因之一。定位第七句Alcohol, hunger, too much talking, breathing through the mouth during exercise—anything that dries the mouth produces bad breath.（酒精、饥饿、说话太多、运动时用嘴呼吸，任何使口腔干燥的东西都会产生口臭）可知，C项“太多的运动”也符合原文。定位到第二段倒数第四句So can stress, though it’s not understood why.（压力也是如此，虽然不知道为什么），以及第五句Some people's breath turns sour every time they go on a job interview.（有些人每次去面试时口气都会变酸）可知，压力也会造成口气问题，而D项“精神紧张”并不是压力问题，属于曲解原文。因此，该题选择D项。
38.【试题答案】D
【试题解析】推理判断题。题干意思是“根据这篇文章，酒精与口臭有关的主要原因是……”。定位文章最后一句If the mouthwash contains alcohol—as most do—it can intensify the problem by drying out the mouth.（如果漱口水中含有酒精—大多数漱口水都含有酒精—会使口腔干燥，从而加剧这一问题）可知，含有酒精的漱口水会使口腔干燥，从而产生口臭，原因是唾液流动变得缓慢，那么推断，酒精与口臭有关的主要原因是因为使得口腔唾液流动缓慢，所以D项“它影响唾液的正常流动”正确。A项“它可以阻止有害细菌的繁殖”是漱口水的作用，并不是酒精，属于张冠李戴。B项“它的气味增加了死亡的危险”和C项“它杀死一些有益的细菌”没提到，属于无中生有。因此，该题选择D项。
39.【试题答案】B
【试题解析】事实细节题。题干意思是“漱口水不能有效治疗口臭，主要是因为……”。定位到最后一段，Some mouthwashes claim to kill the bacteria responsible for bad breath. The trouble is, they don’t necessarily reach all offending germs. Most bacteria are well protected from mouthwash under thick layers of mucus.（一些漱口水声称能杀死导致口腔异味的细菌。问题是，它们不一定能触及所有有害细菌。在厚厚的黏液层下，大多数细菌都能很好地免受漱口水的侵害。）可知，漱口水不能治疗口臭是因为厚厚的黏液层覆盖了有害细菌，所以漱口水不能触及到所有的有害细菌，B项“它们不能接触到所有有害的细菌”正确。A项“它们不能长时间掩盖臭味”，这和治疗口臭无关，属于出处错位。C项“它们强烈的气味和口臭混合在一起，使情况更糟”没有提到，属于无中生有。D项“它们不能覆盖厚厚的黏液层”属于曲解原文，漱口水不能治疗口臭的原因是厚厚的黏液层使得漱口水不能接触到所有的有害细菌，并不是不能覆盖厚厚的黏液层的原因。因此，该题选择B项。
40.【试题答案】A
【试题解析】推理判断题。题干意思是“从这篇文章我们可以推断出……”。文章前两段描述了引起口臭的多种原因，包括酒精、饥饿、说话太多、运动等使口腔干燥的因素，后两段阐述了能够增加唾液流动和掩盖口臭的方法，综合可以推断，引起口臭的因素有很多，所以并不是很容易治好，A项“口臭不容易治好”正确。定位第二段倒数第二句Saliva flow gradually slows with age, which explains why the elderly have more bad-breath trouble than younger people do.（随着年龄的增长，唾液的流动会逐渐减慢，这也解释了为什么老年人比年轻人更容易出现口臭问题），原文提到了老年人比年轻人更容易口臭的原因，但B项“老年人对口臭不太反感”并未提及，也无从推断，属于无中生有。原文提到了酒精会使口腔干燥，从而导致口臭，所以酗酒者更加受到口臭的影响，C项“酗酒者受口臭的影响较小”和D项“口臭受酒精的影响较小”都属于反向干扰。因此，该题选择A项。
