问题详情：
A chicken lays an egg. You feel sleepy. And a tree loses its leaves. All of these things, and many more, happen in a certain way, at a certain time each day or each year. They take place because of something called an internal clock. The word internal means “inside of”, and the internal clock is inside a certain part of every plant and animal. For example, there is an internal clock in the head of a chicken.
The internal clock receives a signal, a message, from the world around it. Some of these signals include light, heat, darkness and cold. When the internal clock gets the signal, the body of the plant or animal produces a chemical that causes the living things to do different actions. For example, daylight signals the chicken’s internal clock to make a chemical. Then this chemical causes the chicken to lay eggs.
People are learning a lot about internal clocks. Farmers have even learned how to fool a chicken’s internal clock so that the chicken lays more eggs!
1. A signal is_________.
A. a chemical B. a message C. internal D. inside
2. The clock described in the story is called internal because it_________.
A. means “inside of” B. is inside every plant or animal
C. never stops running D. produces a signal
3. In this story, one signal would be__________.
A. cold weather B. a chemical C. falling leaves D. a sleepy dog
4. In the chain of events below, what is missing?
Daylight acts A chicken’s internal ? The chicken
as a signal. clock receives the signal. lays an egg.
A. The chicken moves its body. B. The chicken is fooled by the farmer.
C. The chicken makes a chemical. D. The chicken sees the daylight.
5. What do you think farmers do to make chickens lay more eggs? They________.
A. make the chickens do different actions B. keep the chickens in a cooler place
C. feed the chickens a special chemical D. turn on lights in the chicken house at night
【回答】
1B 2B 3A 4C 5D
知识点：日常生活类
题型：阅读理解
