I hope I will not be called on in class asI’m not yet ____ prepared.

One of the main themes of the summit was “sustainable development”,or the question _________ we can continue developing the world without damaging the environment.

The street is too bad，isn’t it?—_______,_______it’s a bit too crowded.

different life today is from what it was thirty yearsago!

was no hard evidence, most people thought he had broken the window of the classroom.