A
Losing a baby tooth can be fun for a kid. You can put it under your pillow and look forward to finding some money there in the morning. And then you can watch your new permanent(永恒的）tooth grow in its place.
But if a permanent tooth falls out, that's a problem. There isn't another one under the gum（齿龈）that can replace it. Unfortunately, this happens to some older people. And if permanent teeth fall out or need to be pulled, an older person might need dentures.
Dentures,known as false teeth, are a set of replacement teeth for any teeth that are missing.
There are partial dentures, which take the place of only a few teeth and prevent the others from changing position. If all the teeth are gone, the person would need complete dentures,which replace every tooth in the mouth.
Dentures can cause pains at first but take little time to get used to.They also need special care. They should be brushed daily with a special denture brush and cleanser and soaked(浸泡） in denture solution when not in the mouth.
Dentures are important for the old because, without teeth, it's hard to smile, talk, and eat properly. But it can be a little weird if you see someone take out his or her dentures. It can also be strange to see someone, like a grandparent, without dentures in because he or she won't have any teeth. Try not to make fun of the person because this could cause hurt feelings.
People usually lose their permanent teeth due to periodontal disease (牙周炎）， or gum disease, which is caused by bacteria that attack the gums. Diseased gums aren't strong and healthy, so teeth can get loose and fall out. Older people often have many cavities (洞） that have been filled over the years, and these fillings can weaken over time, leading to more tooth problems.
1. If one of your baby teeth falls out, you_______
A. should have a false tooth fixed in its place
B. will gain a permanent tooth in future.
C. have to put it under your pillow at once
D. can exchange it for some money
2. A person wearing dentures_________
A. will experience unpleasant feelings at the beginning
B. will spend a very long time adjusting himself or herself to them
C. should brush them with a special denture brush every few days
D. should use denture solution to soak them in his or her mouth
3. Which of the following is NOT true according to the passage?
A. Partial dentures can prevent the remaining teeth from changing position.
B. Old people will find it hard to smile, talk, and eat properly without teeth.
C. A person's teeth will possibly get loose if diseases strike his gums.
D It is hard for a person to wear dentures if all his teeth have fallen out.
4. What does the underlined word "weird" mean in the fifth paragraph?
A. inconvenient B. excited C. strange D. impolite
【答案】1. B 2. A 3. D 4. C
【解析】
【分析】这是一篇说明文。文章对假牙的作用和重要性进行了说明。
【详解】1.细节理解题。根据第一段最后一句“And then you can watch your new permanent(永恒的）tooth grow in its place.”（然后你就可以看到你的新恒牙在原来的地方生长了。）可知，当乳牙掉后，会有一颗新的恒牙长出来，故选B。
2.细节理解题。根据第五段第一句“Dentures can cause pains at first but take little time to get used to.”（假牙一开始会引起疼痛，但很快就会习惯。）可知，戴假牙在刚开始时会产生疼痛，需要一段时间来适应，故选A。
3.细节理解题。根据第四段第一句“There are partial dentures, which take the place of only a few teeth and prevent the others from changing position.”（有部分假牙，它只能代替几颗牙齿，防止其他牙齿改变位置。）可知，局部假牙可以防止剩余的牙齿改变位置，所以选项A正确，排除A；根据第六段第一句“Dentures are important for the old because, without teeth, it's hard to smile, talk, and eat properly.”（假牙对老年人很重要，因为没有牙齿，就很难微笑、说话和正常饮食。）可知，老年人会发现没有牙齿就很难微笑、说话和正常饮食，所以选项B正确，排除B；根据最后一段“People usually lose their permanent teeth due to periodontal disease (牙周炎）， or gum disease, which is caused by bacteria that attack the gums. Diseased gums aren't strong and healthy, so teeth can get loose and fall out.”（人们失去恒牙通常是由于牙周病或牙龈疾病，这种疾病是由攻击牙龈的细菌引起的。患病的牙龈不结实不健康，所以牙齿会松动脱落。）可知，牙龈生病的话，人的牙齿可能会松动，所以选项C正确，排除C；根据第五段“It can also be strange to see someone, like a grandparent, without dentures in because he or she won't have any teeth. ”（看到像爷爷奶奶这样的人因为没有牙齿而没有戴假牙也会很奇怪。）可知，牙齿全掉的人也是可以戴假牙的，所以选项D错误，故选D。
4.词义推测题。根据画线词后的“It can also be strange to see someone, like a grandparent, without dentures in because he or she won't have any teeth. ”（看到像爷爷奶奶这样的人因为没有牙齿而没有戴假牙也会很奇怪。）中的also可知，前后两句呈承接并列关系，所以前后句想表达的意思相似，所以weird在此处的意思应为奇怪，故选C。
