疼痛不剧烈，可以忍受，绵绵不休是 A．胀痛 B．重痛 C．空痛 D．隐痛 E．酸痛

如图所示，半圆形光滑槽固定在地面上，匀强磁场与槽面垂直．将质量为m的带电小球自槽A处由静止释放，小球到达槽最低点C处时，恰好对槽无压力，则小球在以后的运动过程中对C的最大压力为

（　　）

A．0

B．4mg

C．5mg

D．6mg

阅读《门槛》中的一段文字，回答下列小题：
姑娘跨进了门槛。——厚厚的门帘立刻放下来遮住了她。
“傻瓜!”有人在后面咬牙切齿地咒骂。
“一位圣人。”不知从什么地方传来这一声回答。

最后一句评价表现了什么

Besides providing a perfect environment for sea plants and animals to live in, seawater has other values, one of which is that it constantly moves, and its movements produce energy.

The most obvious movements are the waves and the tides. Winds cause the waves, and the gravitational pull of the moon and the sun causes the tides. In places like the Bay of Fundy in Canada, the difference between the high and low tide level can be as much as 40 feet.

France and Britain are now trying to use energy in the tides to produce electricity. Waves can produce electricity and some experiments are taking place to learn more about this. One of the most encouraging areas of research uses the difference between the temperature of seawater at the surface and deep down to produce electricity. 

小题1:Waves and tides are caused by ________ .

A．the same forces

B．different forces

C．their own movements

D．plants and animals小题2:It can be inferred from the passage that __________ .

A．waves as well as the energy in the tide can produce electricity

B．the highest tide is 40 feet higher than the lowest one at the sea

C．many countries in the world have made the most of energy produced by seawater

D．it is being tried in some developed countries to use energy in the tides to produce electricity小题3: The best title for the passage is ______.

A．Tides and Waves

B．How to Produce Electricity

C．Seawater

D．Another Cheap Energy

物质丙是重要的化工产品，在国民经济中占有重要地位．工业上用甲和乙合成丙．甲、乙、丙的微观示意图见下表．

物质	甲	乙	丙
微观示意图

（1）甲、乙、丙三种物质都是由（填“分子”、“原子”或“离子”）______构成的．

（2）甲、乙、丙中属于化合物的是（填序号）______．

（3）已知物质丙中氢元素的化合价为+1，则另一种元素的化合价为______．

（4）甲和乙合成丙的反应中，甲、乙、丙的微粒个数比为______．

（5）现有10g的甲和60g的乙混合反应制取丙，反应一段时间后，经测定剩余甲的质量为4g，则剩余乙的质量为______g．

下列能转化生成儿茶酚胺的氨基酸是

A．蛋氨酸

B．脯氨酸

C．酪氨酸

D．色氨酸

E．天冬氨酸