2010年高考英语一轮复习题库
21. Unfortunately, when I dropped in, Doctor Li _____ for Beijing to join in the fight again SARS, so we only had time for a few words.
  A. just left B. has just left C. is just leaving D. was just leaving
22. He hasn\'t come yet. What do you consider _______ to him？
A. happens B. has happened C. happening  D. to happen
23. ______ is known to us all is that China has launched Shenzhou V