You'll pass the finals as long as you study hard this week.

as 在这里是连词，表示"在...情况下"或"当...时"。 long 本义是"长的"，在这里与 as 搭配构成短语。 as long as 是一个固定短语，表示"只要"或"条件是..."，用来引出某个条件或前提。