问题
选择题
--The classroom is __________ clean __________ it was yesterday.
--Sorry, I forgot to clean it.
A．as; as
B．so; as
C．not so; as
D．more; than
答案
答案：C
题目分析：句意：教室不如昨天干净，对不起，我忘记打扫了。not so(as)…as…,不如，是同级比较的否定，故选C。