과거에 할 수 있었던 일에는 could + 동사원형을 써요. could 뒤에는 to를 쓰지 않아요. I could to swim이 아니라 I could swim이에요.
could + 동사원형
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.". could와 동사 사이에는 아무것도 들어가지 않아요. to도 쓰지 않아요.
해 보세요: When Amina was five, she ___. (could swim / could to swim / could swimming) 정답: could swim — could 뒤에는 동사원형만 단독으로 써요. could swim처럼 써요. could 뒤에는 "to"나 "-ing"를 붙이지 않아요.
누구에게나 같은 형태 (-s 없음)
could는 절대 변하지 않아요. he, she, it에도 could를 똑같이 쓰며, 뒤에 오는 동사에도 -s를 붙이지 않아요.
I could speak English.
She could speak English.
They could speak English.
Not "She could speaks English." — say "She could speak English.". she와 함께 쓰더라도 동사는 원형 그대로예요. 절대 could speaks처럼 쓰지 않아요.
해 보세요: When she was young, Sofia ___ French. (could speak / could speaks / coulds speak) 정답: could speak — Could에는 절대 -s를 붙이지 않고, 뒤에 오는 동사도 원형 그대로 써요. ("could speaks"나 "coulds"가 아니라) could speak예요.
부정문: couldn't
할 수 없었던 일에는 couldn't + 동사원형을 써요. (couldn't는 could not의 줄임말이에요.)
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.". couldn't 뒤에는 동사원형을 써요. found가 아니라 find예요.
해 보세요: Hiroshi ___ his keys this morning. (couldn't find / couldn't found / didn't could find) 정답: couldn't find — 부정문은 couldn't + 동사원형이에요. ("couldn't found"나 "didn't could"가 아니라) couldn't find라고 써요.
질문: Could를 맨 앞에
질문할 때는 주어 앞에Could를 두고, 뒤에 동사원형을 써요.
Could you swim at five?
Could she speak French?
What could you do?
Not "Did you could swim?" — say "Could you swim?". 질문할 때는 Could가 맨 앞으로 가요. 'did'는 필요 없어요.
해 보세요: ___ you ride a bike when you were six? (Could / Did could / Were) 정답: Could — 주어 앞에 Could를 놓아 질문을 시작해요. Could you ride a bike?처럼 써요. could 앞에 "did"를 붙이지 않아요.
해 보세요: Remember what follows could, As a child, Lani ___ a bike. (could ride / could rides / could to ride) 정답: could ride — could 뒤에는 항상 동사원형을 써서 could ride가 돼요. (-s, "to", "-ing"는 모두 붙지 않아요.)