Open the brackets and write the sentence using the Present Perfect or the Past Simple.

To form the sentence using either Present Perfect or Past Simple tenses, we must consider the context of the sentence provided. The choice between these two tenses depends on when the action took place or its relevance to the present moment. 1. **Present Perfect Tense:** - **Structure:** Subject + have/has + past participle (e.g., completed, eaten, arrived) - **Usage:** It is used to describe actions that happened at an unspecified time before now, actions that have an effect on the present, or actions that are still relevant. 2. **Past Simple Tense:** - **Structure:** Subject + past simple form of the verb (e.g., completed, ate, arrived) - **Usage:** It is used to describe actions that happened at a specific point in the past and are complete. We need the content of the sentence to determine which tense is appropriate to use. The completion of the sentence might look like: "By the time the meeting started, Sarah (to work) on the project for 5 hours." - In this case, the correct verb form in the brackets is "had worked," which is the Past Perfect tense. This tense is used to show the order of past events when one event occurred before another. The sentence in full would then be: "By the time the meeting started, Sarah had worked on the project for 5 hours." - If the context in which the action occurred is different, the use of Present Perfect or Past Simple may vary, requiring careful consideration of the time frame and relevance of the action.