the older my grandfather gets,___his hair is.1 thin 2 thinner 3 the thinnest 4 the thinner
问题描述：
the older my grandfather gets,___his hair is.1 thin 2 thinner 3 the thinnest 4 the thinner
选择哪一个,及为什么
答
4,the+比较级；the+比较级,是固定搭配,表示越.就越.