Just like fingerprints, each person’s DNA is ______ unless he has a twin.
--- I hear you ________at Smith’s.--- Yes, I________there for about three months.
-----He should have come to join in the thorough cleaning. -----He________, I think. It’s not his turn.
In recent years_________global warming is becoming________concern for people all over the world.
. At ______ thought of competing with them I felt hopeless; however, I actually came ______first!
---It seems that she doesn’t like the dinner very much. ---______. In fact, she’s been on a diet following the doctor’s advice.