An old saying used for forecasting（预测）the weather says, “Red sky at night, sailors’ delight. Red sky in the morning, sailors（水手）take warning.” Is the saying true? It turns out that it is. A red sky at sunset may mean that there are clear skies to the west, where the sun sets. A red sky at sunrise usually means that the clear weather has already passed, so storms might be coming.

Forecasting the weather has been practiced for thousands of years. In the 5th century BC, the Greeks sent out forecasts to sailors. They used signs in nature to forecast the weather. But today, meteorologists send exact forecasts further in advance（提前）. They use scientific instruments to study weather conditions around the world and make forecasts. Pilots, farmers and many other people depend on these forecasts. Luckily, most of us can simply look on the smart phone or turn on the TV to find out what kind of weather is coming.

If you are looking for some signs of the weather, pay attention to nature. There are two basic rules used in weather forecasting: Weather generally moves from west to east, and low air pressure（压力）usually means rain or snow. So pay attention to the signs. If rainbows form in the west at sunrise, the sun is on the way. Smell the flowers-their smells are stronger in wet air. What are the ants doing? Are they moving to higher ground? This could mean a drop in air pressure. Are the birds flying low or high? Falling air pressure may influence birds’ ears, so they fly low. And if the sky is red at sunset, you might plan a picnic for the next day!

1.What is the old saying about?

A The beauty of sunrise.

B The night sky.

C The signs of the weather.

D The sailors’ work.

解析：选C。C. 句意理解题，由“Red sky at night, sailors’ delight. Red sky in the morning, sailors（水手）take warning.”可知，当晚上出现red sky，水手会很开心，当早上出现red sky，水手就要警惕了。所以这是天气的讯号。

2.What does the underlined word “meteorologists” mean?

A The persons who give daily weather reports on TV.

B The persons who carry out research on natural history.

C The persons who take an interest in plants and animals.

D The persons who do scientific studies of weather conditions.

解析：选D。D.词义猜测题，由“They use scientific instruments to study weather conditions around the world and make forecasts. ”可知这个人会预测天气，所以选D做科学的研究。

3.How does the writer develop his idea in Paragraph 2?

A By listing the reasons for terrible weather

B By telling a true story about weather forecasting.

C By introducing different ways of forecasting the weather.

D By mentioning the difficulties in forecasting the weather.

解析：选C。C. 细节理解题，通过介绍古代和现代的不同预测天气的方法来印证作者的理论。

4.What do we know from the last paragraph?

A It’ll be sunny if ants move to higher places

B The smells of flowers are stronger in wet air.

C Birds fly higher because of the low air pressure.

D It’ll rain if rainbows form in the west at sunrise.

解析：选B。B. 细节理解题，A选项“What are the ants doing? Are they moving to higher ground? This could mean a drop in air pressure.”可知蚂蚁往高处爬是因为低气压，而“low air pressure（压力）usually means rain or snow.”低气压则意味着会下雪或下雨，所以A错误；C选项 “Are the birds flying low or high? Falling air pressure may influence birds’ ears, so they fly low.”C错误；D选项“ If rainbows form in the west at sunrise, the sun is on the way.”可知D错误。

5.What is the writer’s purpose in writing the text?

A To encourage people to get close to nature.

B To express the need for weather forecasting.

C To explain nature can tell us about the weather.

D To discuss how important weather forecasting is.

解析：选C。C. 主旨大意题，全文讲的都是通过自然现象去观察天气，可知选C。