相关1Youshouldknockatthe的文学知识

问题详情：根据句意及汉语提示写出单词 （每空限一词）1.Youshouldknockatthedoorbeforeyou________________(进入)theroom.2.Duringthe_______________(二十)century,mobilephonesbecomepopularallovertheworld._________...