While there are some differences in the educational systems in many countries in the world, education itself is ______.

—You don’t look well! What’s the matter?—My son is _______ to computer games. And I have no idea what to do with it.

Not everyone has realized what_______ important part the balance of________ nature plays in their life.

As economy worsened, jobs ______ to the laid-off workers continued to be scarce． 

 _______ on the fact, the report should be reliable.