_____ is known to all is that effective measures should be taken to deal with the problem of the over-exploiting of our resources.
I regret____that we can’t stay here any longer.
I met him____________________. A. the first time B for the first time C. in the first time D. at the first time
He was the best_____playing chess.
As is known, mobile phone make it possible for people to____each other conveniently.
She knocked ________a cup of tea.