It was obvious that the Climate Change Conference in Copenhagen______the global environmental problems.
A. aimed on B. focused on
C. intended for D. commented on
The students all wear the same uniform,so it’s hard for me to ________my son among them.
A.bring out B.pick out C.pick up D.break out.
Not recognizing me at first, __________.
A. he closed the door B. the door was closed
C. the door was close D. I closed the door
She was always _____ , even when things were at their worst.
A. attractive B. optimistic C. pessimistic D. frightened
This also keeps the air，soil，water crops________ chemicals.
A.out of B.out from C.free of D.rid of
____polite to others and you can get friendship in turn.
A. Be B. To be C. Being D./
