man in a black hat is my PE teacher. He often playsfootball with us.

How long does it take you to get to school?一_________

Though they are twins, they are not always__________ each other.[ ]

It is safe to eat chicken that________fully, but most people still dare not do that because of the H7N9bird flu .

It’s very difficult to see ____ the window because the glass is very dirty.[ ]