---What do you thin of the book?---Oh, excellent. It’s worth _______ a second time.
What animal can live both ___ land and ___ the water.
Mr Chen was ___ early thirthies when he went abroad to have his further studies.
Children often get presents ___ Christmas and ___ their birthdays.
You can find the new hospital ___ the end of the street.
___ the end of this new term we'll have graducated from middle school.