In the past few years, so many areas throughout the world have been hit by such destructive earthquakes, snowstorms and tsunamis ________ we have never experienced before, ________ makes us worried a lot about nature disasters

more about our university courses, write to this address.

My new novel has disappeared.Who _______ have taken it?

It become much _______ to provide enough energy for a big city with large population.

________ from Milan Trenc’s novel，the film Night at the Museum brings to life a world where dinosaurs wander the earth