下列句子中，加粗的成语使用恰当的一句是 [ ] A．钻石一般都是无色的，有色钻石

患者，女性，36岁，发热、头痛7天，加重伴意识丧失2天，体检：体温38．2℃，呼之能睁眼，但不能正确回答问题，颈抵抗（+），双侧瞳孔对光反射灵敏，压眶反射时可见四肢活动，动度一致

对诊断最有价值的检查是（）。

A.头颅CT及CTA

B.脑电图

C.头颅MRI及MRA

D.血常规、血生化和肝肾功

E.腰椎穿刺，脑脊液常规、生化和细菌培养

将玉米种子纵剖开，可以看到如图所示结构：

（1）①______具有保护种子内部结构的作用．

（2）在剖面上滴一滴碘液，能被染成蓝色的是图中的______（填数字）．

（3）③将来发育成______．

（4）③④⑤⑥合称______，将来发育成______．

（5）种子萌发时，⑥______最先突破种皮．

孔板测流量时，若将孔板装反，变送器指示将偏大。

阅读理解。

     The average temperature around the world is rising. People living in the US Midwest might find this

fact hard to believe, though. Two new studies show that in America's heartland, summers are now cooler

and wetter than they were in years past. The scientists suggest that the change in the Midwest climate

may have happened because of farming.

     The first study was led by David Changnon, a climatologist at Northern Illinois University in DeKalb.

A climatologist studies the climate of an area, which includes measuring rainfall, temperature and wind.

Climatologists want to know how these factors have changed in the past, and how they will change in the

future.

Changnon and his team studied temperature records from Chicago and 13 other sites in the Midwest.

"These two changes -lower temperatures and more rainfall-may be connected by humidity," Changnon

says. Humidity is the measure of how much moisture is in the air. Humid air, which contains a lot of

moisture, takes longer to heat up than dry air.

     So where did the extra moisture in the air come from? Changnon points to farms in the region. As

plants grow, they pull moisture from the ground and release it into the air. And among plants, soybean

and corn plants release a lot of moisture. Midwestern farms now plant more soybeans and corn than in

the past, with 97 percent of farmland today planted with these two crops. He also notes that the plants

are planted closer together now than they used to be, so there are more plants per acre than in the past.

     The second study was led by famous scientists from the US. The researchers studied a vast area of

the United States that stretches from South Dakota to Oklahoma and the Texas panhandle. They found

that in 1930, farmers in that region irrigated only about 1.8 million acres of farmland, an amount roughly

half the size of Connecticut. In 1980, however, farmers irrigated nearly 15 million acres-more land than

Vermont and New Hampshire combined.                              

1. What does the underlined word "changes" mean in Paragraph 3?

A. It means that the temperature is lower and the rainfall is higher than before

B. It means that the rain is heavier than before

C. It means that the weather is cooler and there is also more rainfall than before

D. It means that our mind should be changed about farming in the future

2. From this article, we know that____.

A. the weather will be changed in the future

B. farmers irrigated nearly 15 million acres in 1930

C. we must plant more trees in order to protect our environment

D. the climatologists have told us two aspects about the reason for the climate change

3. The underlined word " moisture" in Paragraph refers to ____.

A. humidity          

B. rainfall            

C. water          

D. steam

4. The best title for the article is ____.

A. The Weather Is Changing Better Now        

B. The Analysis for the Weather

C. Why Climate in Midwest Is Changing        

D. The Importance for Plants and Irrigation 

酸雨是过度燃烧煤和石油，生成氮硫的化合物，溶于水生成硫酸和硝酸的缘故。某次雨水分析数据如下：c(SO₄^2-)＝2.6×10^-5 mol·L^-1，c(Cl^-)＝8.0×10^-6 mol·L^-1，c(NH₄⁺)＝3.0×10^-6 mol·L^-1，c(Na⁺)＝

1.0×10^-6 mol·L^-1，c(NO₃^-)＝2.4×10^-5 mol·L^-1，则此次酸雨的pH接近于(1g8＝0.9)[ ]

A．6.5

B．5

C．4.1

D．4.8