25．Can you explain ____ most deserts are located near the west coast of the continents?
| A．why is it that | B．why it is that |
| C．how it is that | D．how is it that |
These continual _____ in temperature make it impossible to decide what to wear.
| A．alterations | B．vibrations | C．waves | D．fluctuations |
The illness from which Mary is suffering has now been _____ as hepatitis (肝炎).
| A．diagnosed | B．determined | C．deduced | D．discovered |
A completely new situation is likely to _____ when the school leaving age is raised to 16.
| A．arouse | B．rise | C．arise | D．abide |
I must go now. _____, if you want that book I'll bring it next time.
| A．Incidentally | B．Accidentally |
| C．Occasionally | D．Subsequently |
Achieving a high degree of proficiency in English as a foreign language is not a mysterious _____ without scientific basis.
| A．process | B．practice | C．procedure | D．program |