In the global economy, a new drug for cancer, _________ it is discovered, will create many economic possibilities around the world. 

Judy is popular with everyone because she says what she means, ________ she means what she says.

I'll make some sandwiches, just ________ we get hungry later.

__________ you understand the rule, you will have no further difficulty.

We shouldn’t drink _______ we drive and we mustn’t drive if we’ve drunk.

Natural disasters are happening more frequently than before;        the whole world should work together to respond.

______ you come across some new words, don’t refer to your dictionary at once but guess their meanings according to the context.

---- How long was it ______ you finally reached your goal of becoming a doctor?
---- Five years.

You have failed two tests. You’d better start working harder, ____ you won’t pass the course.

—Did you return Fred’s call?
—I didn’t need to ____ I’ll see him tomorrow.