1.hateful本意“为令人讨厌的”,这要看题目本身的意思,如果这件事本身令人讨厌,则对；如果仅仅是“我i最讨 厌的事”,则用the thing I hate most
2.普通：I hate doing this most.
强调句：It is(was) this thing that I hate doing most.
表语从句：This is what I hate doing most.
主语从句：What I hate doing most is this thing.
（此句用主语从句很累赘,为中式英语,不推荐,所以以下省略）
3.把2中的hate全部换成enjoy即可……
4.This is the most unforgettable thing.
5.普通：This makes him pride/sad most.
强调句：It is（was） this thing that makes him pride/sad most.
6.正确