have been doing と have done

前者は、子供たちが今でも庭園で遊び続けています。後者は、完了というより、「その庭園で遊んだことがある」という、経験の意味で受け取れるため、違和感があります。遊びが完了していることを伝えたいなら、次のように言いいます。

They have just played in the garden.
They have just finished playing in the garden.

過去形でもいいです。
They played in the garden.
They were playing in the garden.

日本で英語の現在完了形を習うとき、”They have played in the garden.” という、骨組みだけを習っていますでしょうか。実際の日常生活では、完了なのか、経験なのか、意味が伝わりやすいように、何か言葉を付け加えて言います。

完了の意味なら、
They have just played in the garden.
They have just finished playing in the garden.
They have already played in the garden.
Have they played in the garden yet?
They have not played in the garden yet.

経験の意味なら、
They have played in the garden before.
They have not played in the garden before.
Have they played in the garden before?
Have they ever played in the garden?
They have never played in the garden.

ちなみに、観賞用に整備された庭園が garden で、子供が遊ぶ家の庭は yard と言います。

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kevin@musicolingo.com