The work he devoted his time to _____ worth praising.
______ it have been the failure to pick up directions from the ground control that caused the air crash?
The one concern for parents and students is ______ if the student pursues their university education in a foreign country, the student will not have the opportunity to establish social contacts in China.
Not until the train pulled into the next station ______ her suitcase gone.
In class, fewer of the students who are not ___ their studies sometimes ____the dying robots, not listening attentively.
Ladies and gentlemen, please ______ seated until the plane has come to a complete stop.