不是代詞,whether是連詞,意思是是否,例如:
1、Whether we need more food depends on how many people turn up.我們是否需要更多的食物,這要視到場人數而定。
2、I asked whether they could change my ticket.我問他們是否可以給我換票。
3、Your lawyer can advise you whether to take any action.你的律師可以告訴你是否起訴。