Mark was a student at this university from 1999 to 2003, ____ , he studied very hard and was made Chairman of the Students' Union.
They tried to prevent the damage ________ their cattle.
His father disappeared, ________ two children and never _______ from again.
Does the way you thought of ________ the water clean make any sense?
In order not to be disturbed, I spend three days _______ in my study.
He tried to ________ in Japanese.