走S型车辆的逃费特征是怎样的？

下列叙述没有错误的是（　　）

A．氧化反应不一定是化合反应，但化合反应一定是氧化反应

B．物质与氧气的反应一定是氧化反应，且氧气是一种常见的氧化剂具有氧化性

C．工业制氧气是分解反应，且氧气的密度比空气大，易溶于水

D．催化剂就是能够加快化学反应，而反应前后质量和化学性质都不变的物质

Alice: How are you, Peter?      

Peter: __________[ ]

A. Fine, thanks.  

B. Guess.  

C. Great.    

老年心力衰竭患者，过度应用利尿药的危险包括（）

A.加重肾功能不全

B.降低对血管紧张素转化酶抑制药（ACEI）的反应

C.导致应用ACEI时出现低血压反应

D.增加使用β-受体阻滞药的危险

E.电解质紊乱

煤场的（）煤要经常清除，以免氧化。

No one knows how man learned to make words. Perhaps he began by making sounds like those made by animals. Perhraps he grunted like a pig when he lifted something heavy. Perhaps he made sounds like those he heard all around him water splashing, bees humming, a stone falling to the ground. Somehow he learned to make words. As the centuries went by, he made more and more new words. This is what we mean by language.
People living in different countries made different kinds of words. Today there are about fifteen hundred different languages in the world. Each contains many thousands of words. A very large English dictionary for example, contains four or five hundred thousand words. But we do not need all these. Before you leave school, you will learn only a few thousand of them.

In order to make a speech, we need sounds and words.

A. Right.

B. Wrong.

C. Doesn’t say.