A good teacher must be able to hold his students’ attention ____ he reaches the end of the class.
| A．when | B．after | C．until | D．unless |
In order to _____ the rising production costs, the subscription rates have been increased.
| A．add up to | B．look up to | C．cut short | D．keep up with |
Although Lucy was slimming, she found cream cakes quite _____.
| A．irregular | B．inevitable |
| C．incredible | D．irresistible |
Thomas Edison considered genius to be _____ one per cent inspiration and ninety-nine percent perspiration.
| A．composed of | B．constituted in | C．consisted of | D．comprised in |
All foreign visitors are requested to _____ with the regulations in this area.
| A．agree | B．comply | C．consent | D．conform |
These continual _____ in temperature make it impossible to decide what to wear.
| A．alterations | B．vibrations | C．waves | D．fluctuations |