All living organisms (有机物), __________ their unique identity, have biological, chemical and physical characteristics in common.
A number of students _______ said they were forced to practice the piano.
---- Can I sit in the front row?----Yes, you can take ________ seat you like.
Its hard to ________ the green beans from the red ones, because there are too many of them.
Never before _______ seen anybody who can play tennis as well as Robert.
______ her roommates, the girl stepped into the room quietly.