The key to exercise solutions in chapter 2c - Grammar in use for the textbook On Screen B1+ - Student's Book with authors Virginia Evans and Jenny Dooley from Express Publishing
Question
Read the examples in the table. When do we use the past simple / present perfect?
Put the verbs in brackets into the past simple or the present perfect.
Answer
We use the past simple for a completed action at a specific time in the past. We use the present perfect for an action that started in the past and continues to the present.
1) hasn't rained; 2) happened; 3) Did you hear; 4) haven't flown; 5) did the fire start