26. It is difficult to do some of the experiments ________ in our physics textbooks.
| A．to describe | B．describing | C．described | D．being described |
A qualified doctor has to constantly update his knowledge in order to maintain his professional _____.
| A．conscience | B．competence | C．conservation | D．convenience |
We all consider _____ significant that we should cancel the order immediately.
| A．how | B．which | C．this | D．it |
_____, everyone present was amused by his adventure story in Africa.
| A．Absurd as might it sound | B．As it might sound absurd |
| C．As absurd it might sound | D．Absurd as it might sound |
_____ they are fit, I see no reason why they shouldn't go on playing basketball for another four or five years.
| A．In case | B．Provided that | C．Unless | D．As if |
It was not until dark ______ he found ______ he thought was the correct way to solve the problem.
| A．that; what | B．that; that | C．when; what | D．when; that |