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