Our teacher is always busy preparing lessons until 11 o’clock at night, _______we students have gone to sleep.
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.