It is a phrase that is commonly said and it doesn’t compare any two things, so it is an idiom.
Answer:
Sometimes I think my cat has more cents than my sister
It’s supposed to be sense instead of cents.
Hope this help ヾ(≧▽≦*)o
Answer:
The background knowledge that when he was treating humans and kept pets, people stopped coming to him for treatment and he became poor.
Explanation:
While reading the story, Sweet T must have read of the time when Doctor Dolittle was treating humans and kept a lot of pets. People did not like the animals and they soon stopped coming to him for treatments. He began losing money and soon became very poor.
This background knowledge would help Sweet T make the inference that since pet owners were scared of bringing their sick pets to Dr. Dolittle, he would be losing money and would soon become poor again.
