—Have your read the article A Dirty Beijing, which is about air pollution?—Yes. It’s highly informative. I _____no idea that the PM2.5 there sometimes reached 300.
Charles did what he could _____ the servant, although he himself was in danger.
-What do you think of the book? -Oh, excellent. It is worth _____ second time.
When it comes _________ ourselves at the weekend, he would talk about his fishing experiences in the countryside.
--The apple tastes very nice. Could I have another apple, Sir? --_________.
_________ first time I met him in his office, he shook me by _________ hand warmly and then introduce himself to me.