Though lacking________, the young teacher manages the class very well.

His latest research is at the   of genetic science. 

—Do I need to give a tip if I eat at a fast food restaurant in the United States?—Yes , it’s a common       to tip waiters in a restaurant.

Antarctica holds 90% of the world’s ice, and most of its fresh water (70%) is in a frozen          .

  —Nowadays the doctors are trying their best to reduce the people’s fear__________ they would be affected by the present disease called “Bird Flu （禽流感）”.