You do not understand

When Martin Jiang asked him this, the man hesitated for a long time, not knowing what to say.
The person next to him hurriedly whispered, "Idiot! Don't you know Deng Kairui?"
"Isn't he from Dadu? He is from Dadu, how...how would I recognize him?" the man stammered.
"Are you an idiot? You don't even recognize Deng Kairui? Don't you watch TV? He's a celebrity on TV every day, an expert invited from abroad! He's an authority in our Long country!" The companion next to him said angrily.
"This...