In order to go to a key university, I must______my study from now on.

 A. consist of      B. get away from   C. concentrate on    D. come up with

I must ________my watch，it's slow．

[　　]

— Hello, Kate! Nice meeting you here! Working again, are you?

— Yes,          , if I want to pass the exams.

A. I’ve got to                      B. I’m used to

C. I must do                       D. I have one way

Jack, _____ friend, went back to America last Monday.

A me        B I     C my        D mine