17. Angel Books has --- that an increase of e-book services could have worrying effects on the publishing industry.
a. warned
b.warning
c.to warn
d.been warned
19. I would welcome the chance to try out the many techniques that I have mastered ----Dr. Benton's supervision.
a. in
b.on
c.under
d.by
문제 해설좀 부탁드려요ㅠㅠ
3
