hard to come by - difficult to obtain

　　have a heart - have kind feelings; be understanding

　　have a hunch - have an idea based on feelings rather than reason

　　hold off - delay;postpone

　　hop to it - get started on something quickly

　　hit it off - get along well with someone

　　ill at ease - uncomfortable

　　in hot water - in trouble

　　in the air -uncertain

　　in the dark - keep someone without knowdge; information from somenoe