水中碱度实际指（）离子的含量。

甲山的海拔2500米，乙山的海拔1000米，两山的相对高度是    (    )

A．1500来

B．3500米

C．1000米

D．500米

In May, 1976, Gaynor was a nine-year-old girl and lived in North Wales. One day, on her way home from school, she saw a silver(银色的)object(物体)in a field not far from her home. The object looked like a saucer.

Gaynor was very scared. She stayed behind the tall grass and watched the door of the strange object open. She saw two aliens wearing silver suits get out. Then they used something to examine(检测)the ground. They were short and had pink eyes. After about thirty minutes, the two aliens went back into the object. Then it took off.

When Gaynor got home, she told her mother about this unusual experience, but her family decided to keep quiet about it. They didn’t want others to laugh at their daughter.

However, 18 months later, Gaynor told her story to UFO scientists. They found out that Gaynor told the truth.

小题1: Where did Gaynor see the UFO?

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小题2: What did Gaynor see when the door of the UFO opened?

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小题3: What did the two aliens do?

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小题4: What did the two aliens look like?

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小题5:Why did Gaynor’s parents keep quiet about her unusual experience?

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"善意"相对人是指（）致使民事行为效力待定的事由的相对人。

A.无意中知道了

B.不知道也不应当知道

C.不应当知道却知道了

D.应该知道却不知道

下列各句中，没有语病的一句是（     ）

A．素质可以理解为人在先天条件的基础上，在家庭、社会的影响下，经过后天的教育所形成的稳定的心理品格。

B．当今的环境保护技术不仅做到了生产过程不浪费资源，不污染环境，保证产品使用的清洁高效，而且产品使用后废弃物的有效回收和循环利用。

C．在新形势下，我们应该树立新的文化发展观，推进和挖掘文化体制创新和特色文化内涵，着力开发富有时代精神和广东特色的文化产品。

D．对调整工资、发放奖金、提高职工的福利待遇等问题，文章从理论上和政策上作了详细的规定和深刻的说明，具有很强的指导意义和可操作性。

下列哪种物质不是细菌合成代谢产物

A．色素
B．细菌素
C．热原质
D．抗毒素
E．抗生素