And just as in a job interview, you'll be on your best behaviour and so on, behave that way.

工作面试时候，你会有最佳言行举止，这里同样。

I want you both to be on your best behaviour at Grandad’s.

【behaviour，behavioural，behaviourally】我希望你们俩在爷爷家里一定要规规矩矩的。