阅读理解。
Have you ever seen a horse with toes (脚趾)? Millions of years ago, horses had many toes. They had
four toes on each front foot. They had three toes on each back foot. The horses were smaller than cats.
These small horses lived in the forest. Their many toes helped the horses run over the soft wet ground.
It was very hot in the forest. But the weather changed. It became cold. Many trees couldn't live in cold
weather. The trees died and fell. Open field took the place of (代替) forests. The sun made the ground dry
and hard (坚硬).
Horses began to change too. They began to get bigger. This took a long time. On the dry hard land,
horses needed only their middle toes for running. Their middle toes became hard. After a long time horses
had only one hard toe on each foot. We call this hard toe a hoof (马蹄).
1. Long ago, the horse had four toes on each of its ______.
A. back feet
B. front feet
C. right feet
2. The cats were ______ the horses at that time.
A. much bigger
B. smaller than
C. bigger than
3. Which of the three sentences is true?
A. The weather stays the same the whole year all over the world.
B. When the weather changed, animals began to change too.
C. Cats were bigger in the past than they are today.
4. On the dry hard land ______.
A. horses needed a lot of room for running
B. a horse needed more than four toes for running
C. horses needed only their middle toes for running
5. Now each horse has ______ on its feet.
A. one toe
B. three toes
C. four toes