Ⅰ.语法填空
(2016·石家庄市模拟)Dogs are __1__ very popular pet. Most of them just live with their families. But some dogs have very special jobs __2__ (do). A group of dogs __3__ (know) as “Therapy Dogs”. These dogs are family pets with special training, __4__ allows them to go into public buildings and comfort people __5__ need. The dogs are trained to be calm and quiet. Loud noises and unfamiliar places don't frighten them. They enjoy spending time with people.
