—Excuse me，may I have a word with Mr. Zhang？—I’m afraid he’s not_______now．He’s having a class upstairs．

Researches show that the taller you are, the more _______ you are to suffer back pain.

After two years’ research, we now have a _______ better understanding of the disease.

The police failed to come up with ______ evidence, and on that account the suspect was released.

Despite their good service, most inns are less costly than hotels of _____ standards.