Give two examples of types of companies that would be best able to handle high debt levels.

Companies that manage local telephone service and those that manage natural gas delivery to consumers would be expected to comfortably be able to handle high debt levels.  This is for the reason that the sales of these two kinds of companies tend not to react very much to the business cycle.  Their sales tend to increase with increase in the population.  They are often protected and regulated from competition although this isn't thus much true as it was a few years ago.