23. Bear in mind that no part of this book may be reproduced ______ written permission from the author. (A) unless (B) when (C) without (D) for

32.(A) The organizer is usually anonymous, but generally give the name Bill. (B) After their silly performance or action, they just disperse in different directions all of a sudden. (C) A flash mob is a group of people who mostly do not know each other before they congregate and take action. (D) Most groups simply want to have fun.