Chocolates

Xiao YuYi's heart skipped a beat while it started beating fast due to nervousness. She was afraid to speak knowing that Xiao FengYin knew whether it's a lie or truth. 

"I... I'm awake.. at night.. To eat something.." Xiao YuYi claimed while pretending to look at her plate, but she almost chocked while avoiding to look at Xiao FengYin. 

Although it's an excuse, Xiao YuYi somehow feel relieved to say those words since she didn't lie aside from the truth that she was there to pretend as her twin sister. 

Thanks for having a high IQ which made Xiao YuYi think of the best excuse. She deliberately used the word 'awake' than 'woke up' to make sure she's telling the truth. 

Moreover, it was true that Xiao YuYi did eat something at night but had second thoughts to say what it was. 

Xiao FengYin's raised an eyebrow. He was not convinced after Xiao YuYi had avoided his gaze. His sister never lied to him but he felt something is strange.