听力原文:M: I'm not quite sure how to use this calculator you lent me. I dropped it, and now the on-button doesn't light up. W: Oh, that's okay, it hasn't been working right for some time now. Q: What was the man's problem? (14)
【单选题】Tourists become perplexed because they dont know street names are posted on the side of buildings, rather than on signs. The underlined part means______.