10kV及以下架空线路严禁跨越( )。A．河流 B．金属屋面 C．爆炸性气体环境

在△ABC中，∠C=90°，若AC=5，BC=12，则AB等于（　　）

A．13

B．14

C．15

D．16

阅读理解。

     Our climate is changing around the world. Because of man-made pollution, the earth is becoming warmer

and warmer. The 1990s were the warmest ten years and the 20th century was the warmest century.

     There are many signs of the climate change around us. In Europe, the glaciers (冰川) of the Alps are

disappearing and the droughts in the Mediterranean are worse than before. Southern Spain is turning into

desert. And, as ice melts, sea levels all over the world are rising.

     We are in danger because it will rain less because of the hot weather. In Southeast England there used

to be much rain. but the amount of rain will drop by half in the next 40 years. Fewer people may die from

cold in winter. but many more could die from heat in summer. In the summer of 2003, about 20,000 people

died from heat in France and soon happened in Britain.

1. What makes the earth warmer and warmer?

A. The waste of water.

B. The heat of summer.

C. The heavy rain.

D. Man-made pollution.

2. Which is one of the signs of the climate change?

A. The number of people in the world is growing.

B. There is more snow than before.

C. There isn't much water as before in the Mediterranean.

D. It is very cold in winter.

3. What can cause the rise of sea levels?

A. The melting of ice.

B. The reducing of rain.

C. The cold weather.

D. The strong wind.

4. When win the amount of rain in Southeast England drop by half?

A. Next year.

B. Two years later.

C. In the next thirty years.

D. In the next forty years.

5. This passage is mainly about the _______.

A. change of climate

B. disappearance of glaciers

C. pollution of the air

D. droughts in the Mediterranean

下图1是基因型为AaBb某自花传粉的植物的胚珠中胚和胚乳发育的示意图。请分析回答：

(1)图中①可能的基因型有_____种，若该图中胚乳细胞的基因型是aaaBBb，则胚芽的基因型应为______。

(2)图中②将发育成__________，其基因型为_________________。

(3)若该胚珠形成的种子播种后长成的植株表现为显性性状，生产上鉴定其是杂种还是纯种的最简便的方法是__________________。

“一国两制”构想创造性地将和平共处原则用来处理（）。

A.一个国家的内部问题

B.国与国之间关系问题

C.国与国之间争端问题

D.国与国之间历史遗留问题

普通热处理分哪几类？