_____the activities might seem childish, actually they require a lot of strength and determination

— How much is the latest style of the watch?— Sorry, I have no idea. But it and I will know the price soon. [ ]

The visitors said that they had never dreamed ______ such a beautiful scenery[ ]

________ that China has the largest population in the world

It is required by law that the children above six years old in our country ________ to school to receive education.