An excellent teacher is believed to be one who devotes himself to the children but asks for nothing _______.
| A．in return | B．in advance | C．in short | D．in turn |
Professor Smith will come here to give a speech．All the preparations must be _____ before 5 o’clock．
| A．in time | B．in sight | C．in place | D．in control |
---Is everything settled?
---Not yet．_____ I approached the problem, I couldn’t find a solution．
| A．Whatever | B．However | C．Whenever | D．Wherever |
The retired professor, _____ in his new book in the past three years, hasn’t realized the decline in his health．
| A．involved | B．being involved |
| C．having involved | D．to be involved |
With the final exams coming, Mark, the top student in our class, is not worried about Chinese, and _________ English．
| A．still more | B．at least |
| C．least of all | D．better than |
It puzzles the scientists _____ some mammals produce their young _____ others lay eggs．
| A．that; while | B．what; while | C．that; as | D．what; as |