Below, a stands for full-name quantifier and e stands for existential quantifier.

Let f (x): x be a train, g (y): y be a car, and h (x, y): x run faster than y.

Direct symbolization is Ex(F(x)∧Ay(G(y)→H(x, y)), which can be converted into exact (f (x) ∧ (g (y) → h (x, y)) according to the contraction and expansion of the definition domain, which is the toe-in paradigm.