单选题 If Mr. Thomas has his office blinds closed, ______ means he does not want to be disturbed.
【正确答案】 B
【答案解析】选项A错误，“then”后面跟主语或者祈使性动词时应省略，但主句缺少主语。选项B正确，代词在主句中代替了主语名词。选项C在句子不以“if”开头，且在“closed”后面有一个分号时才是正确的。选项D错误，“which”引导一个从句。