1 多两个 / 少两个
Two more
Two less(不可数)/two fewer(可数)
2 多了两本书 / 少了3本书
多了两本书/少了3本书-two more books/ three fewer books
3 我比你多3本书
I have three more books than you do. / I have three books
more than you do.
她比我少了4本书
She has four fewer books than I do. / She has four books fewer than I do.
这里是比较谁的书多,所以不能说I have more books than you, 因为这样听起来你在用你的书比较人家的人,而不是人家的书。就像是在说“我有的书比我有的你多“
P.S. jenaljoke 的语法全错了。