We use present perfect:
- To talk about past experiences when we don't say when they happened. If we say when they happened (minutes ago, yesterday, in a date) we use the past simple.
- To give news if something has happened recently we often use just
- We use present perfect with yet to ask if something has happened, or to say that it hasn't happened but that it will.
- We use the present perfect with already to say that something has happened earlier than expected.
- To talk about situations that started in the past and have continued to the present.
- To express a period of time we often use for or since
- for + period of time : for two months
- since + a time in the past : since this morning
- We can use phrases with all to express a period of time
- To express a period of time we often use for or since
all my life for all my life
all day for all day