Young students are ______ not to smoke both in and out school. 

 In our childhood, we were often ___ by Grandma to pay attention to our table manners.

With more and more farmers moving to cities, an inadequate labor force is ________ becoming a major factor affecting the country's grain output.

Tom couldn’t ___ those forms until I had explained how to do it twice.

______jobs will be lost if the company closes down.