Could / Couldn't (A1)

Usa could + el verbo tal cual para algo que podías hacer en el pasado. Sin to después de could: I could swim, no I could to swim.

could + verbo tal cual

When Amina was five, she could swim.
Hiroshi could ride a bike at six.
I could read when I was four.
Not "She could to swim." — say "She could swim.". Nada va entre could y el verbo, sin to.
Pruébalo: When Amina was five, she ___. (could swim / could to swim / could swimming) Respuesta: could swim — Después de could, usa el verbo tal cual, solo: could swim. Sin "to" y sin "-ing" después de could.

could nunca cambia. He, she, it también usan could, y el verbo que va después no lleva -s.

I could speak English.
She could speak English.
They could speak English.
Not "She could speaks English." — say "She could speak English.". Incluso con she, el verbo se queda tal cual, nunca could speaks.
Pruébalo: When she was young, Sofia ___ French. (could speak / could speaks / coulds speak) Respuesta: could speak — Could nunca lleva -s, y el verbo que va después también se queda tal cual: could speak (no "could speaks" ni "coulds").

Para algo que no podías hacer, usa couldn't + el verbo tal cual. (couldn't = could not.)

She couldn't find her keys.
I couldn't swim when I was three.
They couldn't come yesterday.
Not "She couldn't found her keys." — say "She couldn't find her keys.". Después de couldn't, el verbo va tal cual, find, no found.
Pruébalo: Hiroshi ___ his keys this morning. (couldn't find / couldn't found / didn't could find) Respuesta: couldn't find — El negativo es couldn't + el verbo tal cual: couldn't find (no "couldn't found," y no "didn't could").

Para preguntar, pon Could antes de la persona, luego el verbo tal cual.

Could you swim at five?
Could she speak French?
What could you do?
Not "Did you could swim?" — say "Could you swim?". Para una pregunta, Could va primero, no necesitas 'did'.
Pruébalo: ___ you ride a bike when you were six? (Could / Did could / Were) Respuesta: Could — Empieza la pregunta con Could, antes de la persona: Could you ride a bike? No añadas "did" antes de could.
Pruébalo: Remember what follows could, As a child, Lani ___ a bike. (could ride / could rides / could to ride) Respuesta: could ride — Después de could, siempre el verbo tal cual: could ride. (Sin -s, sin "to", sin "-ing", siempre.)