I wondered what difficulty he had _________the plan

the fact _______there is plenty to see, itwould be better if you made a list before hand of ______exactly you want to go.

I think students should have mobile phones to call their parents.—___________. They often use them to play games, instead.

Nowadays children should learn to ______ other children.

It was announced that only when the examination papers were handed in ________to go out of the classroom．