méiyǒu réngōng jiǎngjiě shí èrwēimǎ shuōmíngpái hé lùxiàntú dōu hěn yǒuyòng

没有人工讲解时，二维码、说明牌和路线图都很有用。

When there is no tour guide, QR codes, information boards, and route maps are all very useful.