Fill in the blanks, each using one of the given words or phrases

Fill in the blanks, each using one of the given words or phrases below in its proper form.
stand for   exposure to   at work   on the edge of   short of   end up   focus on   a host of   give off   a sense of   in memory of   comply with
_________ problems may delay the opening of the conference.
【正确答案】：A host of