cook something up
phrasal verb with cook verb uk/kʊk/ us/kʊk/
informal
编造，捏造
to invent a story, plan, etc., usually dishonestly
She cooked up some weird scheme that was going to earn her a fortune. 她想出了个能使自己发财的怪点子。
I had to cook up an excuse about my car breaking down. 我只好编个借口说车子出了故障。