冷不防

冷不防，老師讓每個國家的學生用話筒給大家講一下自己來哈爾濱的原因。

lěngbùfáng lǎoshī ràng měigè guójiā de xuésheng yòng huàtǒng gěi dàjiā jiǎng yíxià zìjǐ lái Hāěrbīn de yuányīn

Without warning, the teachers ask students from each country to take the microphone and explain to everyone their reasons for coming to Harbin.