题目内容
After that first tooth comes out, more and more teeth begin to appear(出现). Most kids have their first set(副)of teeth when they are 3years old. These are called baby teeth and there are 20 in all. When a child grows to 5 or 6 years old, these teeth start falling out, one by one.
The baby teeth fall out because the permanent teeth(恒牙) grow and take the place of(取代) the baby teeth. By the age of 14, most kids have lost all of their baby teeth and have a full set of permanent teeth.
There are 28 permanent teeth in all-eight more than the original(原来的) set of baby teeth. At about the age of 20, four more teeth called wisdom teeth(智齿)usually grow at the back of the mouth. And you have all your 32 teeth.
B. his teeth haven’t begun to grow yet.
C. one can’t see his teeth.
D. he has only a few teeth.
B. 4 years old
C. 5 years old
D. 6 years old
B. are 8 more than baby teeth
C. begin to grow at the age of 14
D. will be replaced by wisdom teeth.
B. 24
C. 28
D. 32
B. If you have a good habit , you won’t lose your baby teeth.
C. Wisdom teeth usually grow in the front of the mouth.
D. Your heart and brain are ready to work for you when you are born.
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