A
The zebra belongs to the horse family. One of nature’s great mysteries is why the zebra has stripes(条纹). One theory is that the stripes help the zebra cool down. On hot days the black stripes get a lot hotter than the white area of the zebra and under the black stripes there are special layers(层) of fat for protection. Hot air then rises off the black stripes, forcing colder air down around the white areas, cooling the zebra down This, however, is just a kind of theory. The stripes can also confuse predators(食肉动物，掠食者)when zebras stay with other animals in great numbers.
Zebras have excellent hearing and eyesight and can run at speeds of up to 56 kilometers per hour. They also have a powerful kick that can cause serious injury to a predator, like a lion, or an African wild dog. Usually the lead male of the herd stays at the back of the group to defend against predators if necessary, while the females and youngsters escape danger.
Zebras are herbivores that feed only on plants and lives mostly by eating grasses, although they also might eat a bit of the leaves and stems of bushes. They eat grasses for many hours each day, using their strong teeth. Spending so much time chewing wears the zebras’ teeth down, so their teeth keep growing all their lives. As the dry season arrives and the grasses die back, zebra herds travel to find more food and water holes for drinking. Most zebras have no specific territories. They travel from place to place, never staying in one area very long.
1. It can be inferred from the first paragraph that _____________.
A. there are different opinions about why the zebra has stripes
B. the black stripes help the zebra live through cold days
C. the zebra can be easily attacked by predators
D. the zebra always travels with other animals
2. According to the passage, herbivores are animals that ___________.
A. have specific territories B. only eat plants
C. kill and eat other animals D. live in groups
3. The zebra has strong teeth all their lives because their teeth ___________.
A. only chew soft grasses B. are used all day
C. are always growing D. are kept clean
