Vocabulary and idioms review C2

My new colleague is keeps trying to undermine me, even though he's super friendly to me - he's definitely a ____ in_____'s clothing

Pat never changes his mind once he's decided something - he's as _____ as a ______

Dave's got a ____ in his _____ about finishing the marathon in under 4 hours - he's mad!

When I told my boss the real reason I was leaving, it certainly put the ______ amongst the _____

Jane decided to take the _____ by the _____ and tell her boss that she's leaving

I kept trying to get my mates interested in chess but they were just so bored - I was just flogging a dead___

Clare has lived in many countries and is an expert in _______ communication (CULTURE)

During COVID, most ________ workers were working from home or temporarily out of work (ESSENTIAL)

I told my mum I'm dropping out of university and she's having......

His strong opinions were often based on social media posts and not much else - he was extremely _____ in his beliefs (GUIDE)

Say whatever you like about my work - it's like _____ off a _____'s back for me!

______ of school property will not be tolerated! (USING)

The argument was over so I decided to let sleeping ____ lie, and not mention the issue again