13 - Present Perfect/Simple Past - I have done - I did

Study this example situation:

Ellen is looking for her keys. She can't find it. She has lost her keys. ( present perfect). This means that she doesn't have her keys now.

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TEN MINUTES LATER...

Now Ellen has found her keys. She has them now.

Has she lost her keys? - present perfect
No, she hasn't . She has found them.
Did she lose her keys? - past simple
Yes, She did.
She lost her keys. - past simple
But now she has found them. - present perfect.
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