_____ you understand the rules of the game, you will enjoy it.
| A．Before | B．Even if | C．Once | D．While |
It______ a calm head to find the best solution to such a difficult problem within a short time.
| A．costs | B．takes | C．spends | D．needs |
By the end of 2007，about half a million people had flooded into the city，______ up around 10 percent of its total population.
| A．make | B．made | C．making | D．to be made |
Jumping out of ______ airplane at ten thousand feet is quite ______ exciting experience.
| A．/；the | B．/；an | C．an；an | D．the；the |
_____ on the MSN，some people often use “88” for “goodbye”．
| A．When chat |
| B．When chatting |
| C．When chatted |
| D．When to chat |
At the meeting they discussed three different ______ to the study of mathematics.
| A．approaches | B．means | C．methods | D．ways |