He has alreadyworked for--------hour A.an B.a C.the D.three 想问D哪里错了
问题描述：
He has alreadyworked for--------hour A.an B.a C.the D.three 想问D哪里错了
答
因为 hour 在做“小时”讲的时候是可数名词
如果选D ,题干应为：He has already worked for--------hours.
本题hour 为单数,故A选项为正确选项.