a host of rivals的用法和样例：
- THE U.S.CURRENCY is getting pummeled by a host of rivals from the euro to the yen, but not every contender is giving the dollar a thrashing.
- A host of friend meet him at the railroad station.
- A host of friends met him at the railroad station.
- A host of compelling socioeconomic problems.
- Our era produces a host of heroes and heroines.
- I'm sure the audience has a host of questions for our team of experts.