Completing text with words exercise

[D.Alex]

Could you please hel me with a correction of an open cloze exercise ?

Flashmobbing is the latest craze to hit Europe from
the United States. Seemingly spontaneous crowds are
created by calling people via the internet to do something
unexpected, (1) ​

by lying down on the floor for a
period, and then disappearing as quickly as they arrived.
Europe’s first flashmob took (2) place
in Rome when people went to a shop and asked staff
(3) for books that did not exist. The latest New
York flashmob caused consternation in a toy store
(4) for flash mobsters gathered recently.
Participants (5) were told to stare at the store’s
giant animatronic dinosaur for three minutes then fall to
their knees and react to (6) the roars by moaning
(7) in four minutes. But panicked staff quickly
shut off the dinosaur and called the police (8) for a minute into the mass-moaning. (9) The June
flashmobs have sprung up in around 40 locations and one
seems to be taking place (10) __________ in the world
every few days. But some hope (11) that craze
could die out as (12) __________ as it started thanks to the
over-interested media and over-reaction by the police.

 

[Tdol]

Check 4, 7, 8, & 11.