20.—Is that Dec. 21, 2012 is the end of the world true? —Definitely not, but________must be paid to the global climate change.
---Why didn’t you tell me the truth about his illness? ---___________, I knew nothing about it at that time.
---I am afraid that I have to trouble you with this question. ---___________.
--How long are you staying ? -- I don’t know . ______.
The Olympic Games are held _____.
This area experienced ____ heaviest rainfall in ____ month of May.