(In a quiet evening, a duckling and a chicken are talking about the biggest bird in the world…)

Duckling: Good evening, chicken! What are you doing?
Chicken: Good evening duckling! I am watching TV. This is my favorite program!
Duckling: What’s the program talking about?
Chicken: It’s talking about the ostriches （鸵鸟）.They are the biggest birds in the world!
Duckling: Really?
Chicken: Yes. An ostrich can be 2-3 meters high and weighs about 75 kilos.
Duckling: Oh! They are much bigger than us! Are their eggs bigger than ours too?
Chicken: Certainly! An ostrich’s egg can be 15 centimeters long and weighs about 1.7 kilos.
Duckling: They’re about 25 times（倍） bigger than our eggs!
Chicken: That’s right! And they are good at running. Of all birds they run fastest in the world!
Duckling: Really? How fast can an ostrich run?
Chicken: More than 40 kilometers an hour.
Duckling: Wow! An ostrich can run faster than a zebra（斑马）!
Chicken: That’s true! They are my heroes and heroines！