问题 选择题

下列命题中,逆命题是真命题的是[ ]

A. 对顶角相等

B. 如果两个实数相等,那么它们的平方数相等

C. 等腰三角形两底角相等

D. 两个全等三角形的对应角相等

答案

答案:C

阅读理解

阅读理解。

     When people want to know about the weather, they usually go to their radios, TVs, newspapers, or to the

Internet. However, you can also find many weather signs (征兆) among wildlife. A drop (下降) in air pressure

affects small animals in many ways. Mice and deer are good weather indicators. Before a storm, people outside

have observed that field mice come out of their holes and that Deer come down from the mountains.

     Birds are good weather indicators. For example, some birds become irritable (急躁的) and will fight over a

piece of bread. Other birds chirp (叽叽喳喳) and sing just before a storm. It seems they know they won't have

another chance for one or two hours. Birds also look for safe places before a storm. You will sometimes see

birds gathering together on a wire (电线) close to a building. Before the storm, the low pressure makes the air

so thin that birds have difficulty flying.

     It is unusual to see many birds flying overhead in the summertime. Watch for other weather signs if you

see this. If they fly in the wrong direction, they may be flying ahead of a storm.

     By paying closer attention to some important signs in nature, we can become better prepared for any kind

of weather.

1. The word "indicators" in Paragraph 1 probably means ______. [ ]

A. maps

B. signs

C. services

D. stations

2. There will be a storm if birds ______. [ ]

A. make more noise than usual

B. keep quiet

C. come down from a wire

D. share food

3. How can birds feel the coming of a storm? [ ]

A. By feeling the change of temperature.

B. By noticing the change of time.

C. By feeling the change of air pressure.

D. By noticing what other animals do.

4. The best title for the text is ______. [ ]

A. A Storm

B. Air Pressure

C. Mice

D. Weather Signs

单项选择题