—Jack is not in the office at the moment
—Oh, he ______ those who are going to take the driving test in an hour.
A. can have instructedB. must have instructed
C. must be instructing D. will be instructing
From what she has done we can predict that she is ______enough to make up her own decision and behave in a proper way.
A. positive B. severeC. matureD. admirable
Never______ such a difficult problem. It took me almost half an hour to work it out.
A. had I come across B. I had come across
C. did I come across D. I did come across
— Do you remember the first time we met?
—At that time you ______us a lecture.
A. had givenB. were givingC. have given D. gave
Your _______ as a student will be excellent if you develop a habit of reflecting on how you learn.
A. operationB. performance C. growthD．character
The scientists are beating their brains, trying to ______ a solution to the problem.
A. look up toB. live up toC. come up with D. keep up with
