Hi there! You will use "would have" + "past participle" in both of these sentences. These are both examples of the third conditional 1. If Darren hadn't wasted his Christmas bonus gambling in Las Vegas, he [would have gone] to Mexico with us next month. 2. If Darren hadn't died yesterday, he [would have gone] to Mexico with us next month. more info: https://www.englishclub.com/grammar/verbs-conditional-third.htm