阅读下面的短文，根据短文内容, 从短文后的选项中选出能填入文中空白处的最佳选项。（提示：每个选项只用一次，选项中有一项为多余选项）
People started to study (研究)the weather very early. They used many different ways. Some are still useful. Let's have a look!
Watch the sky (天空).
Different kinds of clouds mean (意味着) different weather．How the clouds move also means different weather. Usually. white and high clouds mean good weather. Dark and low (低的) clouds mean bad weather.
Your parents may tell you, "Red sky at night, don't go out. Red sky in the morning, walk for a long time. "Well, this is quite right.
Watch animals.
Look at the birds. Usually, they fly very high in the sky. And this means good weather.
And this means bad weather. Birds also get very quiet before it rains.
Look at the turtles (乌龟). You can see them on the road 1 to 2 days before a rain.
Sometimes, they will stay together and keep quiet, because bad weather is on the way.
| A. Look at the cows. B. Look at the flowers. C. Look at clouds. D. Before bad weather comes, they'll climb to a high place. E. Sometimes the birds fly very low in the sky. F. Look at the red sky. |