To choose the correct verb form to fill in the blank, we need to consider the context of the sentence and the sequence of events. The sentence is about a pair of shoes that the speaker has owned since a specific time in the past when they were a student in Italy. The key here is the word "since," which indicates that the action started in the past and continues to the present. Let's analyze each option: 1. **visited**: This is the simple past tense. It indicates a completed action in the past. However, "since" requires a continuous action from the past to the present, so this option doesn't fit well. 2. **have visited**: This is the present perfect tense, used for actions that happened at an unspecified time before now. This tense doesn't fit with "since," which needs a specific point in time. 3. **had visited**: This is the past perfect tense, which is used to indicate an action that was completed before another action in the past. This doesn't fit well with "since," which requires a present perfect or past continuous form to indicate an ongoing action from the past. 4. **was visiting**: This is the past continuous tense, which indicates an ongoing action in the past. This fits well with "since" because it suggests the speaker was in the process of visiting Milan at a specific time in the past when they acquired the shoes. Therefore, the correct choice is **"was visiting"**. The complete sentence would be: "This is my favourite pair of shoes. I've had them since I was visiting Milan when I was a student in Italy." This choice correctly establishes the timeline: the speaker was visiting Milan at a specific time in the past, and they have had the shoes since that time.