Summary:

The Present Perfect tense is used to talk about past events that have relevance to the present, experiences using "ever" or "never," and repeated actions up to the present time. The structure of sentences in Present Perfect includes:

• Affirmative: Subject + have/has + verb (past participle)
• Negative: Subject + have/has + not + verb (past participle)
• Question: Have/has + subject + verb (past participle)?

It is different from Present Perfect Continuous which emphasizes the duration of an action that started in the past and is still ongoing. The structure of Present Perfect Continuous:

• Affirmative: Subject + have/has + been + verb (ing)
• Negative: Subject + have/has + not + been + verb (ing)
• Question: Have/has + subject + been + verb (ing)?