1\
An impacted wisdom tooth is one that fails to completely rise through the gums -- the term is erupt.
the term is erupt.
2\
Experts say people should have their mouths examined between the ages of sixteen and twenty for placement of their wisdom teeth.
for placement of their wisdom teeth.在句中充当状语对吗?
3\
Scientists say the diet of prehistoric humans probably required more chewing teeth.Life was probably a little rougher on the teeth back then,too.So it was good to have extras.
Life was probably a little rougher on the teeth back then,too.
So it was good to have extras.to have extras 在句中充当什么成份?
4\
After surgery,there can be swelling of the gums and face and some pain.
there can be 这是个什么句型呀,从没见过?