【题目】It doesn't matter ________ you pay by cash or credit card in this store.
A.how
B.whether
C.what
D.why

【答案】B
【解析】句意：在这个商店中用现金或信用卡支付都可以。此处it是形式主语，后面whether...or…引导的主语从句是真正的主语，whether...or…“是...…还是...…都行”。故选B。