Hi Daewon! Well done - Mark didn't take his umbrella to the park, and now he regrets it. Elena bought an expensive dress, and she regrets that too. Here's Mark: Mark: I wish I had taken my umbrella. Let's break that down. Mark used: I wish, with the past perfect. Now remember, the past perfect has 3 parts; a subject, like I, you, he, then 'had' and finally, the past participle, for example, take, took, taken – taken is the past participle. So 'I had taken' is past perfect. So, when Mark says Mark: I wish I had taken my umbrella. he's using 'I wish', with past perfect, to talk about past regrets. Mark regrets something that didn't happen – he didn't take his umbrella, and he wishes he had. But Elena regrets something that did happen: she bought an expensive dress, but she never wore it. So she uses I wish with I hadn't bought – that's a negative past perfect. Here she is again… Elena: I wish I hadn’t bought a rather expensive dress in the sales. One more thing, if you're talking about he or she, don't forget to say wishes instead of wish – so if you're talking about Elena, say 'she wishes she hadn't bought that dress'. Ok Daewon, good luck with your grammar challenge!