用所给词的适当形式填空：
Let's see the penguins_______（one）.
Let him_______（not go）out at night.
—Why do you like dogs?
—Because they are_______（fiend）.
Koalas are kind of _______（interes）.
The animals in the zoo come from five_______（country）.
There are two______（zoo）in our city.