(届山东省济宁市曲阜师大附中高三上学期期中考试英语试卷)It' s a pity that there are many teenagers _____only on-line activity is chatting with their e -pals !
Sir, you ______be sitting in this waiting room. It is for women and children only.
Jack _____ yet, otherwise he would have telephoned me.
I told Sally how to get here, but perhaps I ____ for her.
Michael ______ be a policeman, for he is much too short.
Unluckily, when I dropped in , Dr. Smith ____, so we only had time for a few words.