I love this gag, from a Punch cartoon supposedly composed by AE Housman (it sounds convincingly Housmany to me), recalled by WH Auden, and recalled again by Stephen Fry in his excellent poetry primer The Ode Less Travelled (Arrow, 2007).
Two English teachers are walking in the woods. The first, on hearing birdsong, quotes Wordsworth:
Teacher 1: Oh cuckoo, shall I call thee bird/Or but a wandering voice?
Teacher 2: State the alternative preferred/With reasons for your choice.