21.I lost the book I ____.   
A.have bought    B.bought     C.had bought     D.had been bought  

22.The bus had gone when I ____ at the bus stop.   
  A.have arrived    B.arrived     C.had arrived    D.am arriving   
 
23.Tom ____ of visiting his grandmother,but the bad but the bad weather made him change his mi.   
  A.has thought    B.thought     C.had thought    D.had been thought  
 
24.—Did you meet Tom at the airport?   
    —No,he ___ by the time I ___ there.   
  A.has left;got            B.had left;arrived  
  C.left;arrived            D.left;had got   
 
25.—Why didn't Tom attend the meeting yesterday?  
    —He ____ Beijing.   
  A.has gone to    B.had gone to   C.went to      D.had been to  
 
26.—I ____ to come to help you. —But you didn’t come.   
  A.have meant     B.had meant    C.meant       D.will mean   
 
27.Finally Mary was admitted by Beijing University,for which she___ five times.   
  A.had tried     B.was trying   C.has tried    D.tried   
 
28.—I have bought you the books you want.
 —Oh,good,I ___ afraid you had forgotten.   
  A.was        B.am       C.had been      D.have been
 
29. When Li Ming hurried home, he found that his mother ____already ____to hospital.   
A has; been sent          B had; sent      C has; sent       D had; been sent  
 
30. We ____five English songs by the end of last term.  
 A had learned   B  learned   C have learned   D will have learned 
 
 【答案解析】
  21-25 CBCBB     26-30 BAADA