by precincts(投票站).There are1,774 precincts in lowa,so there are 1,774 caucuses in lowa.Only registered party members can participate in caucus meetings.Caucuses first discuss and debate about all the candidates and then vote. b.primaries:there are two types of primaries:open primaries and closed primaries.In open primaries, anybody can participate in voting.In closed primaries, only registered party members can vote.The first presidential primary is held in New Hampshire a week after the lowa caucus during presidential election year. 2)National party convention formally selects each party's official presidential and vice presidential candidates. Usually the party conventions are held in August.Partyby precincts (投票站). There are 1,774 precincts in Iowa, so there are 1,774 caucuses in Iowa. Only registered party members can participate in caucus meetings. Caucuses first discuss and debate about all the candidates and then vote. b. primaries: there are two types of primaries: open primaries and closed primaries. In open primaries, anybody can participate in voting. In closed primaries, only registered party members can vote. The first presidential primary is held in New Hampshire a week after the Iowa caucus during presidential election year. 2) National party convention formally selects each party's official presidential and vice presidential candidates. Usually the party conventions are held in August. Party