____ H1N1 flu from spreading, our government has taken some effective measures.

The radiation amount of a mobile phone for two half-hour periods per day is equal to ______ to an X-ray for ten seconds.

Many of the children are so accustomed to ______ that they react violently when they hear something different. 

—The hall___ for international conferences is of great importance．—I see, and we are sure to complete it on time．

_____ her help, we were able to finish our work ahead of time.