I could manage to be able to...

Many people ask me about this grammar point:

"I could play soccer"
"I could ride a bike"
"We could eat barbecue"

Actually, it translates into 「サッカーすることができた」 in Japanese, but is used in a different way in English.

"could" usually means "I had the ability to" or "It was possible to", and doesn't say whether you actually did or not. People often use it like this:
"When I was young, I could play with my friends until it was dark",
but NOT like this:
"Yesterday, I could eat dinner at my favorite restaurant",
because "could" doesn't say whether you actually DID eat there.

Also, you can use "could" to talk about possible future plans. If you say "We could go to Jusco", it sounds more like 「ジャスコに行くのはどう？」, NOT like 「ジャスコへ行くことができた」. You use "could" in this way when you want to make suggestions about things you might want to do in the future.

Usually, context makes it clear whether you're talking about the past or making a suggestion with "could".

Past: "I could get candy for 5 cents when I was a boy."
Future: "I could get some candy for you, if you want any."
Past: "He could go to his favorite store any time he wanted to, until it closed 5 years ago."
Future: "He could go to Uniqlo, if he wants cheap clothes."