Dos oraciones completas: punto, punto y coma, o coma + and/but/so. Una coma sola es un error (comma splice).
Los dos puntos van después de una oración completa e introducen una lista o explicación.
Un inciso se abre y se cierra con el mismo signo: dos comas, dos rayas o dos paréntesis.
Estrategia paso a paso
Divide la frase en el hueco: ¿cada lado puede ser una oración completa?
No pongas puntuación entre sujeto y verbo ni entre verbo y complemento.
Trampas habituales
“However” y “therefore” no unen oraciones por sí solos: necesitan punto y coma o punto antes.
Preguntas indirectas (“asked why…”) terminan en punto, no en interrogación.
Ejemplo resuelto
“The museum closed early; the storm had knocked out the power.” Hay dos oraciones completas, así que sirve el punto y coma (una coma sola sería un error).
Preguntas de ejemplo
Intenta responder antes de abrir la solución. Las preguntas están en el idioma del examen.
Pregunta 1
Dificultad fácil≈ 1 min
Arctic terns migrate farther than any other ______ each year they fly from their breeding grounds in the Arctic to the coast of Antarctica and back again.
Which choice completes the text so that it conforms to the conventions of Standard English?
AA. bird,
BB. bird;
CC. bird
DD. bird, which
Ver respuesta y explicación
Respuesta correcta: B. bird;
Explicación
“Arctic terns migrate farther than any other bird” and “each year they fly… back again” are both independent clauses. A semicolon correctly joins two independent clauses.
A comma alone creates a comma splice, and no punctuation creates a run-on sentence. “Which” cannot introduce a clause that already has its own subject (“they”), so “bird, which each year they fly” is ungrammatical.
Pregunta 2
Dificultad media≈ 1 min
The city’s oldest library was designed by architect Rosa Ibarra in 1911 ______ its reading room, lit by a large glass dome, still attracts visitors from around the world.
Which choice completes the text so that it conforms to the conventions of Standard English?
AA. 1911
BB. 1911,
CC. 1911;
DD. 1911, which
Ver respuesta y explicación
Respuesta correcta: C. 1911;
Explicación
Both “The city’s oldest library was designed … in 1911” and “its reading room … still attracts visitors” are independent clauses. A semicolon can join two independent clauses.
No punctuation (A) creates a run-on sentence, and a comma alone (B) creates a comma splice. “Which” (D) makes the second part ungrammatical: “which its reading room … still attracts visitors.”
Pregunta 3
Dificultad difícil≈ 2 min
The town’s oldest surviving building—a stone mill constructed beside the creek in 1784 by the brothers Elias and Jonah ______ now houses a small museum of local history.
Which choice completes the text so that it conforms to the conventions of Standard English?
AA. Whitcombe—
BB. Whitcombe,
CC. Whitcombe;
DD. Whitcombe
Ver respuesta y explicación
Respuesta correcta: A. Whitcombe—
Explicación
The information about the mill is set off from the main sentence (“The town’s oldest building… now houses a small museum”). It opens with a dash, so it must close with a dash.
A comma or semicolon cannot close a phrase that began with a dash, and leaving out punctuation runs the inserted phrase into the main verb “houses.”