I ate it = past simple I have eaten it = present perfect We use both tenses to talk about past events and actions - the difference is that when we use the past simple, we are talking about a completed or finished action in the past, we can use a past time expression when using past simple - eg., I ate fish for dinner yesterday. When we use present perfect we are speaking in general - we are not speaking about a specific time in the past - we do not use past time expressions with present perfect - eg., I have eaten it - sometime in the past I ate it but it's not important to say when. Conversations often start with present perfect and then move into past simple when the speakers wants more information. example:a) Have you ever eaten salmon? b) Yes I have eaten it once before but I didn't like it. a) Oh, really, when did you eat it? b) It was about a year ago, I was on holiday. Notice how the dialogue begins with a general question and then moves into past simple when the speaker asks for specific details. I hope this helps :D

用第二个更合适 I ate it 强调我曾经吃过，与现在关联不大。可以是昨天吃过，也可以是去年吃过。 I have eaten it 侧重 我已经吃过，回答了别人问题，表示与现在有联系，已经吃过了