Human's Best Friend
We know that dogs are human's best friends. They love us
and we love them. However, we're not so sure where they
came from. 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.
Dogs are easy to educate. Well-educated dogs are
sometimes used as watchdogs. A watchdog can stop a
creature that is five to six times bigger. 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. (Adapted from http://www.grammarbank.com)
Choose the correct alternative to have the passive voice from the sentence, in bold type, in the text.
Their lives _______ in danger to save their owners.
a) is put
b) are put
c) was put
d) were put
