In modern society people have to pass various test for professional          so that they can be qualified for a good job.

The mountains form a natural            between the two countries so they have no trade relations in history.

 Due to the widespread ________ of this medical technology，more diseases can be discovered and treated at an early stage.

-- Without a password, you cannot get ___ to the computer system.--- No wonder it doesn’t go to the next step.

--- How do I take this medicine? --- Well, look at the _______.