The traffic slowed down because of the heavy snow in Yushu county, presenting a new __________ to the recovery from the earthquake.
After the war, a new school building was put up _____ there had once been a theatre.
_____, Mother will wait for him to have dinner together.
He will come to call on you the moment he ____ his painting.
____ difficult the task may be, we will try our best to complete it in time.
It was ____ that she couldn’t finish it by herself.