6 Compare the sentences. Which tense is used for an action that happened: • at an unstated time in the past? • at a definite time in the past? (stated or implied)

Решение:

6. Tense Usage Comparison

• At an unstated time in the past: Present Perfect. Example: We've put up the decorations. (When? We don't know.)
• At a definite time in the past: Past Simple. Example: She finished an hour ago. (When? An hour ago.)

Note: The Past Simple is also used when the time is stated or implied in questions about past events, like 'Was the weather good when you were on holiday?' (When? When you were on holiday - time is stated).