题目内容：

One day when I was going for a walk, I found a small egg in the grass. There were little blue dots(点) on it. “__▲__” I wondered. My elder sister was taking science lessons at high school. I knew she could tell me the answer.

When I got home, I watched the small egg carefully. Tap tap tap! The sound came from the egg. A small brown beak (鸟喙) came out from the egg. “It’s a bird!” I cried. I didn’t have to wait for my sister’s answer anymore.

“It must come from the robin’s nest in the front yard,” Mom saw the egg and said. “If we return it to the nest now, its mother will take care of it when it hatches(孵化).” “But I want to keep it as a pet!” I said. “The baby bird needs its mother. And we don’t know how to keep a baby bird.” I knew my mom was right and returned the egg to the nest.

One morning, not too long after finding the egg, my mother called me out to the yard. “Look!” She said. I looked up and saw the baby bird. Its mother was feeding it! It looked strong and happy.

“Aren’t you glad we found the bird’s home?” Mom asked.

“Yes!” I was glad that I had given the baby bird back to its mother.

1.Which of the following can be put in __▲__?

A. What kind of egg could this be?

B. When will my sister come back?

C. Why is there an egg in the grass?

D. How many eggs are there in the grass?

2.How did the writer know it was a bird egg?

A. His mom told him.    B. His sister told him.

C. His teacher told him.    D. He found out by himself.

3.The writer returned the egg because _____.

A. his mom didn’t allow him to have a pet.

B. he didn’t want a bird as a pet.

C. the baby bird was in poor health.

D. he didn’t know how to look after a baby bird.

4.The passage shows us____________.

A. a small egg in the grass.

B. how to keep a baby bird as a pet.

C. the best way to keep a baby bird.

D. different opinions about a baby bird.