I’m sorry to keep you ______ for an hour. Now let’s begin our work.

Mum gives my classmates some sweets _____ a treat at Halloween.[ ]

Not until the stadium of Bird’s nest was completed in the end ____back to their normal position.

The two friends met a bear while they were walking _____ the forest.[ ]

I think saving water is more important than recycling paper in our daily life.— I disagree. Recycling paper is saving water.