A shark can grow and lose up to 30,000 teeth in a lifetime (一生). ……

hard. But our teeth can last a lifetime without breaking to pieces. Why are teeth so strong?A new... (裂缝) from spreading (扩大) and breaking the teeth apart.These findings explain why doctors can examine ……

(用力咀嚼) foods with your teeth. It’s a wonder that our teeth can last a lifetime without cracking (破裂... of the National Academy of Sciences, explains why doctors can examine the teeth of older people and find ……

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A crocodile (鳄鱼) grows about 3,000 teeth in a lifetime (一生). ……

A crocodile (鳄鱼) grows about 3,000 teeth in a lifetime. ……

), lemon juice or ashes (灰烬).Q:How many sets of teeth does a person have during his or her lifetime?A:2+1... to 13, people lose their baby teeth one by one and permanent teeth grow. Wisdom teeth are the last ……

animals. A shark has around 15 rows (排) of teeth. Some sharks can grow 30,000 teeth in their lifetime...物外衣) on their teeth. Fluoride can keep acid (酸) from eating through their teeth. That’s why most ……

of brushing人一生花多长时间刷牙？The average person spends about 35.5 days brushing their teeth during their lifetime...Bad meals in the sky飞机餐为什么不好吃？Why isn’t airplane food very tasty? It’s because our senses of smell ……

. Why can’t you see your wisdom teeth?4. Why can’t you see your wisdom teeth...学语法学语法Why...Why...Because...Because...TUCHONG Let’s get to know what our teeth are used forLet ……

.Some sharks change over 30,000 teeth in their lifetime.Crocodiles can go through at least 3,000 teeth... 13,000Some kinds of snails can have over 20,000 teeth!Some kinds of snails can have over 20,000 ……

) have very strong teeth. They bite (咬) on trees for food. They can chop down (砍断) a tree with their teeth. Why are their teeth so strong? Their teeth have iron (铁) in them. That makes their teeth ……

(海狸) have very strong teeth. They bite (咬) trees for food. They can chop down (砍断) a tree with their teeth. Why are their teeth so strong? Their teeth have iron (铁) in them. That makes their teeth ……

. That’s why we often cut down trees with our teeth. This can stop our teeth from growing too fast... at building houses. No other animals can do this like us. Our secret weapon (秘密武器) is our teeth.Look at our ……

) their own teeth. A shark can replace about 30,000 of its teeth during its lifetime. Shark teeth... hours.         Sharks often replace (替换) their own teeth. A shark can ……

is the hardest part of your body. 2. Humans have two sets of teeth during their lifetime. Sharks have about 40 sets of teeth. ……