We know that dogs are a human's best friend.
They love us and we love them.----. Many
scientists think they came from wolves 15,000
years ago. Although wolves are wild and dogs
are tame, they're still a lot alike. Both wag their
tails when happy and put their tails between
their legs when scared.
A) However, we're not so sure where they came from
B) Some were trained to do more than keep us company
C) Working dogs guide blind and wheel chair-bound people
D) So they're good at finding things using their keen senses
E) Handlers teach the dog how to find specific things
Dogs are easy to educate. Well-educated
dogs are sometimes used as watchdogs. ----.
It is interesting, though, that these dogs,
which can become terrifyingly wild in times
of danger, pose no harm to their owners. In
the face of a threat, they put their lives in
danger to save their owners.
A) There are hundreds of dog species of different colors and sizes
B) A watchdog can stop a creature that is five to six times bigger
C) Dogs have 42 teeth, that is, 10 more than human beings
D) They were able to perceive moving objects from farther away
E) This extraordinary sense of smell itself is a miracle