He flew to Paris two hours ago, he would stay for three days[ ]

Studies indicate that people are more _______ to suffer from back problems if they sit before computer screens for long hours.

Those poor people don’t have enough ____________.They feel （感觉）hungry.

The little boy is dirty from head to foot because he ___ in the mud all morning.

Who ______ it be that hasn’t handed it in yesterday? ——It _______ be Bob. He handed it in yesterday.