科研之友
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<正>September 20 is Love Teeth Day.We use teeth to eat.We need teeth to talk.But do you really know them?Let’s meet the cool"tools"(工具) in your mouth and learn how to protect(保护) them!Meet your teeth牙齿从哪儿来?Unlike(不像) your brain(大脑) or heart,your teeth are not ready to work when you are born.The first tooth usually comes out when a baby is 6 to 12 months old.Then more and more teeth begin to grow.
