可以去掉.
Bill is shorter than I.= Bill is shorter than me.
She is as slim as I.= She is as slim as me.
than或as后面接的其实是一个从句,叫比较状语从句.这种从句一般都是以省略句的形式出现的,如果把每个成分都补充完整,就是：
Bill is shorter than I am short.
She is as slim as I am slim.
但实际英语中没有人这样说.
Bill is shorter than me和She is as slim as me这两个句子其实是不符合正统的英语语法的,传统的英语也不这样说.但现代英语,特别是英语口语常常有人这样说.根据这种变化,语法学家们就把这两个句子中的连词than和as当作介词来看了.