On a very chilly morning, here is a Cultural Literacy worksheet on the idiom “You can’t have your cake and eat it too.” This expression remains in sufficiently common usage that students probably ought to learn it somewhere along the way–if they don’t hear it in social contexts, didactic teaching may be called for. This document might help.
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.