occasionally ----> sometimes
occupy one's time ----> wait a long time
odd ----> surprise
Of course not (mind). ----> welcome
Oh, no. ----> sorry
on edge ----> nervous
on end ----> continuously // for some time // for quite a while
on my own ----> herself
on one's own ----> (by) oneself
on the courtyard ----> outside
on the news ----> on television
on the second floor // take the stairs up ----> on the floor above
on time ----> avoid being late
on your desk ----> in an office
once // no longer ----> not anymore
once and again // from time to time // on and off // off and on ----> sometimes // occasionally
One day's as good as the next. ----> He's available any day.
one in a million ----> rare
one more ----> another
one step at a time ----> gradually
One's job search was unsuccessful. ----> sb. was unable to find a job.
one's schoolwork be suffering ----> be interfering with one's studies
only ----> part
only a couple of times ----> twice // two times
only a ten-minute walk ----> not need to take a car
only occasionally ----> once in a while
only sb. can't ----> almost everyone can
only three of ... ----> most of ... not
only try to help ----> One's intention be good.
optional ----> sb. can do sth. ... if sb. wants to
organize ----> take care of
other than ----> except
ought to be easier // unless ----> might be difficult
out of breath // run // rush ----> hurry
out of date ----> up to date
out of it // in another world ----> think only about
out of order ----> not work // break down
out of print for sometime now ----> no longer available
out of the way ----> finish
out of this world ----> delicious // like sth. very much
outcome ----> result
outgoing ----> friendly
out-of-date ----> up-to-date
outstanding ----> good
over ----> end
over one's head ----> beyond sb. // not understand
overcome her fear of public speaking ----> not afraid to give a speech
oversleep ----> absent
oversleep // on time // in a hurry // inside out ----> be rushed