INGLES

PRESENT PERFECT TENSE We use the Present Perfect to say that an action happened at an unspecified time before now.  The exact time is not important.  You CANNOT use the Present Perfect with specific time expressions such as: yesterday, one year ago, last week, when I was a child, when I lived in Japan, at that moment, that day, one day, etc.  We CAN use the Present Perfect with unspecific expressions such as: ever, never, once, many times, several times, before, so far, already, yet, etc.
Examples:
You have seen that movie many times.
Have you seen that movie many times?
You have not seen that movie many times.

exercises Sue has lost the key of her car.
Has Sue lost the key of her car?
Sue has not lost the key of her car.

Peter has saved almost $7000 for a new motorcycle.
Has Peter saved almost $7000 for a new motorcycle?
Peter has not saved almos $7000 for a new motorcycle.

Jenny has finished her homework.
Has Jenny finished her homework?
Jenny has not finished her homework.

Some boy has broken the windows.
Has some boy broken the windows?
Some boy has not broken the windows.