VOA慢速英语:US Candidates Plan to Stop Trump from Winning Nomination

convention – n. a large meeting of people who come to a place for (usually) several days to talk about their shared work or other interests or to make decisions as a group

ensure – ​v. to make (something) sure, certain, or safe

top of the ticket – expression the presidential candidate; the top candidate

rig – adj. to control or affect (something, such as a game or election) in a dishonest way in order to get a desired result

emerge – v. to become known or regarded as something