Could / Couldn't (A1)

Use could + o verbo no infinitivo para algo que você conseguia fazer no passado. Sem to depois de could: I could swim, não I could to swim.

could + verbo no infinitivo

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 fica entre could e o verbo, sem to.
Experimente: When Amina was five, she ___. (could swim / could to swim / could swimming) Resposta: could swim — Depois de could, use o verbo no infinitivo sozinho: could swim. Sem "to" e sem "-ing" depois de could.

could nunca muda. He, she, it também usam could, e o verbo depois dele não leva -s.

I could speak English.
She could speak English.
They could speak English.
Not "She could speaks English." — say "She could speak English.". Mesmo com she, o verbo fica no infinitivo, nunca could speaks.
Experimente: When she was young, Sofia ___ French. (could speak / could speaks / coulds speak) Resposta: could speak — Could nunca leva -s, e o verbo depois dele também fica no infinitivo: could speak (não "could speaks" nem "coulds").

Para algo que você não conseguia fazer, use couldn't + o verbo no infinitivo. (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.". Depois de couldn't, o verbo fica no infinitivo, find, não found.
Experimente: Hiroshi ___ his keys this morning. (couldn't find / couldn't found / didn't could find) Resposta: couldn't find — A negativa é couldn't + o verbo no infinitivo: couldn't find (não "couldn't found", e não "didn't could").

Para perguntar, coloque Could antes da pessoa, depois o verbo no infinitivo.

Could you swim at five?
Could she speak French?
What could you do?
Not "Did you could swim?" — say "Could you swim?". Numa pergunta, Could vem primeiro, você não precisa de 'did'.
Experimente: ___ you ride a bike when you were six? (Could / Did could / Were) Resposta: Could — Comece a pergunta com Could, antes da pessoa: Could you ride a bike? Não coloque "did" antes de could.
Experimente: Remember what follows could, As a child, Lani ___ a bike. (could ride / could rides / could to ride) Resposta: could ride — Depois de could, sempre o verbo no infinitivo: could ride. (Sem -s, sem "to", sem "-ing", sempre.)