The build-up to an event is the way that journalists, advertisers, or other people talk about it a lot in the period of time immediately before it, and try to make it seem important and exciting.
双语例句
例： The exams came, almost an anticlimax after the build-up that the students had given them.
在学生们一番大造声势之后，随之而来的考试却出乎意料地平淡。