—Fool _____ I am, I will not believe you any more.You have been promising a hundred times!—But Mum, this is the last time.
The bell _______ the end of the period rang, _______ our heated discussion.
The research is so designed that, once _______, nothing can be done to change it.
The most important thing _______ we should pay attention to is the first thing ________ I have said.
_____, the great mother, in order to save her sick child, kept waiting for four hours in the heavy snow.
Was it in 2002 __________ he was still at middle school __________ the boy became expert at computer?