Past simple and
Use the past simple to talk about things that start and finish at a particular time in the past:
I started here in 2009.
From 2012 to 2014 I studied at Heriot Watt University.
+ed for regular forms, watch out for many irregular forms
We talked about the business and thought about some new ideas.
Negatives and questions in past simple:
Use the auxiliary ‘did’ for questions and negatives.
We didn’t like living there.
Did you ask for a discount?
Use the present perfect to talk about things that start in the past but include the present:
I have worked with Peter since 2008 (he still works with Peter—lucky Peter).
Use the present perfect to talk about things that happened in the past but without any specific time information:
I have visited York twice.
Present perfect form:
Use ‘has / have’ + a past participle. We have seen our friends twice this year.
Negatives and questions:
Reverse the verb / subject order for questions.
Have you been to Spain?
Use ‘hasn’t / haven’t, has not / have not’ for negatives.
He hasn’t been to Spain yet.