When the H1N1 virus____ at first in Mexico, no one had the least idea that it would spread so rapidly throughout the world.
--- Shall I go over to have a chat with you this evening?--- Nice of you! It is ____ great comfort to keep me ____ company, when I’m alone at home.
At the age of 29, Dave was a worker, _______ in a small apartment near Boston and ______ what to do about his future.
When he ______the door, he found his keys were nowhere.
In April, 2009, President Hu inspected the warships in Qingdao,_______the 60th anniversary of the founding of the PLA Navy.
______not to miss the flight at 15:20, the manager set out for the airport in a hurry.