The students entered the classroom,smiling and________,and ______ down to have their lessons.
This new-type machine____________ little room.
--You don't look so well, Mary. What's the matter with you? --Why?___________.
China has hundreds of islands, ___________ is Taiwan Island.
Be quiet!Our teacher has _________ to tell us.
Nearly________ of the surface of our planet is covered by water.