PRESENT PERFECT SIMPLE
USE
- Actions and experiences that happened at an unspecified time in the past with ever, never, just, already, yet - Example: I have never visited Asia.
- Completed actions, especially when we express the amount completed. The emphasis is on the result - Example: She has read three books this month.
- Actions expressed by stative verbs which started in the past and continue in the present with for and since - Example: I have known her since college.
VS
PRESENT PERFECT CONTINUOUS
USE
- To emphasise the continuous nature of an action, which has been uninterrupted - Example: She has been studying all day.
- Actions that have been in progress recently (unfinished or recently finished). The emphasis is on the activity - Example: I've been working on this project for the past few hours.
- Actions that started in the past and continue up to now with for and since - Example: They have been living here since 2010.
SIGNAL WORDS
Present perfect simple: ever, never, just, already, yet, so far, recently, lately, before, in 2021, etc.
- Example: Have you ever been to Paris?
Present perfect continuous: How long?, all morning / day, since, for, lately, recently, the whole week, etc.
- Example: How long have you been waiting?