After any preposition, the verb takes -ing
The rule is simple: after any preposition, a verb takes the gerund (the -ing form) — never the infinitive. Prepositions attach to verbs, adjectives and nouns, or come as short words of their own. Pick a head word on the dial and watch the machine fill the slots. (Tras una preposición, el verbo va en -ing: interested in working, no “in to work”.)
1 · Pick a head word on the dial
2 · Watch the slots fill
Gerund or infinitive after the preposition?
Infinitive to or preposition to?
The test: if you can replace “to + verb” with “to it”, then to is a preposition → use -ing. Tap a sentence and run the test. (Si puedes decir “to it”, ese to es preposición: -ing.)
Seven things to watch after a preposition
Errors Spanish speakers make
Read the sentence, find the problem, then tap Fix to check. (Errores típicos: adivina la corrección antes de verla.)
👩🏫 For the teacher — how this page maps to the manual
- Explore is Grammar 11’s two tables as a machine: the dial follows the manual’s groups (verb / adjective / noun + preposition, prepositions on their own) plus the “to” trap as a fifth, purple group; the middle slot turns purple whenever to is a preposition. The “two to’s” card runs the manual’s to it test on exercise-D sentences; the special-cases card follows the exceptions box (to trap, negative gerund, gerund as subject, afraid of / to, possessive) plus by / without / instead of and being from the exercises; the errors card is the pitfall box.
- Build is productive: students assemble a sentence by choosing the preposition and the verb form (exercises A, C and D), then transform two ideas into one sentence with a preposition + gerund (Task set 24 and the mixed review), with validation.
- Drill merges the quizzes into one graded engine (★ which form / which preposition / name the structure · ★★ fix the error & complete (used to wear, good in, by copying) · ★★★ the “to” trap, negative gerund, afraid of / to, join two ideas) with a score and streak.
- Works offline. Reading/writing only — no audio.
Build a sentence
Read the idea and its head word, then choose the preposition it takes and the verb form that follows. The machine assembles the sentence — guess before you check.
Drill — one flow, three levels
★ which form? which preposition? name the structure · ★★ fix the error & complete · ★★★ the ‘to’ trap, not + -ing, afraid of / to, join two ideas. Keep your streak alive. (Igual escalera que tu Cuaderno de tareas.)