The slower ______, the deeper the sleep.

A．Studying for a test.
B．Visiting a close fiend of theirs.
C．A class presentation they’re preparing.
D．A television program the man is watching.

A．One of his classes finished early.
B．His books were ten days overdue.
C．He wanted to get some studying done.
D．The library had a special display on the Industrial Revolution.