I will never know what was on his mind at the time, nor will _______.

___ is reported that he got severn good medals.

Nine in ten parents said there were significant differences in their approach to educating their children compared with __ of their parents.

______ we know, the air quality in the city has improved over the past two years.

---Is there anything I can do for you? ---I’m looking for a book,      written by Han Han.