could you lend me your dictionary?Sorry,I left ------ at hom

我觉得这个应该用it.
跟据上面的句子我们可以看出这样的情景：A向B借字典,B把它忘在家里了.
a:could you lend me your dictionary?
b:Sorry, I left ______ at home.
由于两者都知道所谈论的事物,故用it代替.
如果这句话是一个人说的,用MINE恰当.
could you lend me your dictionary? I left mine at home.
可原句比上句多个SORRY,我觉得不是一个人说的.