Homework on §1.4—assigned Fri 9/4 and due Mon 9/7

Give an example of English sentences φ, ψ, and χ which are such that φ, ψ ⊨ χ but φ ⊭ χ (i.e., the entailment no longer holds if you drop the premise ψ). Use the definition of entailment to explain why your examples are an answer.