The professor has written another book ____ of great importance to computer science.
| A．which I think it is | B．and I think is |
| C．which I think is | D．when I think is |
—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 instructed | B．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．severe | C．mature | D．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 given | B．were giving | C．have given | D．gave |
Your _______ as a student will be excellent if you develop a habit of reflecting on how you learn.
| A．operation | B．performance | C．growth | D．character |