be on fire
be on one's guard
be on one's way
be on sale
be on strike
be on the defensive
be on the market
be on the mend
be on the rack
be on the road
be on the scent
be on to
be one's own man
be oneself
be out
be out of breath
be out of business
be out of one's depth
be out of one's mind
be over
be pleased
be pregnant
be present
be proud
be quick