Final answer:
To maintain the original meaning of the sentence, use the subjunctive mood with the past perfect tense expressing regret about the past event: 'I wish they had not eaten all the pizza'. This conveys the student's wish that the situation had been different.
Step-by-step explanation:
To complete the sentence using the word given, you must use the subjunctive mood to express the student's wishful thinking about the situation. The sentence should be constructed as follows:
When expressing a hypothetical situation in the past, the subjunctive mood is used with 'wish'. In English, we often use the past perfect tense after 'wish' to talk about regrets or situations that we would like to be different. In the provided sentence, 'had' indicates that the situation occurred in the past, so the verb 'eaten' must be preceded by 'not' to reflect the desired opposite outcome.
Therefore, 'I wish they had not eaten all the pizza' means that, unfortunately, they did eat all the pizza, but the speaker wishes that this had not happened. It is also important to keep the structure intact and use the exact words given without changing them to maintain the same meaning as the original sentence. The use of 'had' followed by 'not' and the past participle form of the verb 'eat' achieves this correct restructuring.