Cats’ sense of smell is very important to their health. Many cat owners have seen a cat smell the food and refuses it. Careful sniffing tells the cat if something is safe to eat.

Cats have a pair of vomeronasal organs(犁鼻器) on the roof of the mouth. When the cat wants to sniff, she will breathe the air in through her mouth. At this moment, she will often squint(斜视) her eyes and maybe even flatten(使…平坦) her ears. This makes her look like she is making faces. The vomeronasal organs will then analyze the smell---almost as if the cat is tasting the smell.
When you come home from outside the house, your cat can smell what you had for lunch and for a mid-afternoon snack. She can smell the people you shook hands with and your neighbour you stopped to talk to and hug. She can smell the grass brought under your shoes as you took a shortcut across the lawn. Your cat’s sense of smell is so good that she can smell difference between a gallon of water with a teaspoon of salt in it and plain water. In comparison, we think of salt as completely tasteless.
Cats have scent glands(臭腺) on each side of the forehead, on the chin, the lips and next to the tail. When your cat rubs up against your hand, your leg, the sofa, and your bed, she is leaving her scent in those things. She will then use her sense of smell to recognize “her” things, people and even other pets in the home.
If you want to have fun with your cat’s sense of smell, take some small bits of different things, such as a bit of chicken, some flowers and some fish. Place each different scent under a piece of paper towel(so your cat cannot see any of them) and encourage your cat to investigate and find what kind of food she likes to eat best.
Cats know whether the food is fit to eat or not with their____________.

A．sense of touch

B．scent glands

C．organs of smell

D．sense of taste

The third paragraph was written mainly to prove that _____________.

A．cats are very smart

B．cats have a good sense as dogs

C．salty water has a special smell

D．cats’ sense of smell is excellent

What does your cat do when it rubs against your foot?

A．She puts her scent on it.

B．She shows respect to you.

C．She asks you to play with her.

D．She smells where you were just now.

What does the word “investigate” mean in the last paragraph?

A．Smell.

B．See.

C．Search.

D．Send.

The passage mainly tells us _________________.

A．cats are one of our best friends

B．cats have sharp sense of smell

C．sense of smell is very important

D．cats know if something is safe to eat