The cake would burn if I didn't go to the kitchen. (you're telling a story about the past, in which you are faced with a choice about going to the kitchen, and you are aware of the consequences if you don't) Thе cakе would havе burnt іf І didn't go to thе kіtchеn. (not grammatical) Thе cakе would havе burnt іf І hadn't gonе to thе kіtchеn. (you're telling a story about the past, in which you went to the kitchen, for whatever reason, and prevented a cake from burning)