There is a flea that hasn’t met a dog it didn’t bite

Something is a flea that hasn’t met a dog it didn’t bite

Something is such that (it is a flea that hasn’t met a dog it didn’t bite)

∃x x is a flea that hasn’t met a dog x didn’t bite

∃x (x is a flea ∧ x hasn’t met a dog x didn’t bite)

∃x (x is a flea ∧ ¬ x has met a dog x didn’t bite)

∃x (x is a flea ∧ ¬ some dog x didn’t bite is such that (x has met it))

∃x (x is a flea ∧ ¬ (∃y: y is a dog x didn’t bite) x has met y)

∃x (x is a flea ∧ ¬ (∃y: y is a dog ∧ x didn’t bite y) x has met y)

∃x (x is a flea ∧¬ (∃y: y is a dog ∧ ¬ x bit y) x has met y)

∃x (Fx ∧ ¬ (∃y: Dy ∧ ¬ Bxy) Mxy)
∃x (Fx ∧ ¬ ∃y ((Dy ∧ ¬ Bxy) ∧ Mxy))