(误)London is much hotter in summer than my hometown.
(正)It is much hotter in London in summer than in my hometown.（用it代表气候，天气等。）
(误)His book is quite different from me.
(正)His book is quite different from mine.（mine = my book，应保持比较的双方性质的一致。）
(误)I have important something to tell you.
(正)I have something important to tell you.（修饰something，nothing，anything等不定代词时，形容词应放在其后。）
(误)Every student should do their own homework.
(正)Every student should do his own homework.（every student是单数，其后的代词也用单数。）
(误)I like to receive letters but do not like to write it.
(正)I like to receive letters but do not like to write them.（代词的人称与数应与它代替的名词相同。）