The manager was worried about the press conference his assistant _______in his place, but luckily, everything was going on smoothly.
They are still very cautious about ________ side effect the new medicine will bring about, although the experts have tried it on about 2000 patients.
His opinion was such a good one _________ his family all agreed to accept.
_____ is known to us all that the 2012 Olympic Games will take place in London.
_______ on your study, and you will make greater progress.
—Would you give it another guess?—____ —tell me the answer.