21. —Who do you think is responsible for the boy’s behavior, Mary or her husband?

 —We all think it’s Mary as well as her husband that ________ for their son’s bad performance at school.

   A. are to blame          B. is to be blamed         C. are to be blamed                     D. is to blame

22. The thing for them ________ is ________ to raise enough money for the project.

A. doing, managing   B. to do, manage    C. doing, manage   D. to do, managing

23. This photo was taken in Beijing thirteen years ago. Can you ________ my elder brother?

A. look out               B. work out                  C. pick out                          D. watch out