W: Hi, Mike.
M: Hi, Mary. I overslept again!This really is becoming a bad habit.What did Professor Brown talk about today?
W: We talked about George Washington's false teeth.
M: Oh! All I know is that they were made of wood.
W: Well, that, it turns out, is a myth.A famous professor at a dental school in California recently presented a paper showing that (1)___________________________________________.
M: But why do people say that Washington's teeth were made out of wood?
W: A set of his teeth that were made out of elephant ivory was displayed in exhibitions around the country about a hundred years ago.The ivory had turned a very dark color and I guess it's like wood.
M: Oh, yes. I've seen ivory that has a dark brown color.
W: (2)____________________________________________.I guess that's how the story got started.
M: What's this about cow's teeth?
W: You know, cows have teeth just on their bottom jaws.(3)_________________________________________.So they too, at one time, were used to make false teeth.
M: That's really interesting.Well, this will certainly teach me not to oversleep again.I do wonder what little-known facts Professor Brown will have for us next week.
Washton's teeth were made of things include ,can you image, elephant ivory and cow's teeth but not wood.
It seems that ivory stained quiet easily with age, especially if it was exposed to drinks such as coffen,tea, or wine.
after about 5 years of bite grass of aginst hard upper jaw, the bottom teeth was down into the shape of human teeth.
Washington's teeth were made of the things including can you imagine, elephant and ivory and cow's teeth,but not wood
it seems that ivory stains quite easily with age especially it's exposed to drink such as coffee,tea or wine
after about 5 years of biting grass off against their upper jaw ,the bottom teeth will down into the shape of human tooth
发表于 2014-10-10 09:37
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发表于 2014-10-10 18:00
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