患者女性，28岁，偶有心悸症状。心电图如图5-14所示，应诊断为（）。 A.间歇性预

雨夜的路灯周围有一圈圈彩色光环包围着，这是光的______现象．

受体阻断药的特点是

A．对受体有亲和力，且有内在活性

B．对受体有亲和力，但无内在活性

C．直接抑制传出神经末梢所释放的递质

D．对受体无亲和力，但有内在活性

E．对受体无亲和力，也无内在活性

请以平实的语言表述下面材料中老园艺师一段话的深层含意，不超过25个字。

　　夜幕下, 小松树上彩灯闪烁。路过的老园艺师自言自语  地感慨：“人睡觉要关灯，整夜灯光照着，非失眠不可。树也一样, 那么多的电线缠着，那么强的灯光照着，能活得好吗？夜色是美了，树可是要生病的。人们啊，要听得懂草木的叹息！”

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　　①据英国广播公司（BBC）2006年5月20日报道，冰岛并不存在能源缺乏问题，但这个国家仍然已经找到一种先进的减少石油依赖的方法，努力成为世界上第一个不再使用汽油的国家。　

　　②冰岛是一个岛国，火山喷发使得这个国家简直就是建在火山灰和熔岩之上，熔化的岩浆释放出巨大的热量，地下湖水的温度达到沸点。这些藏匿于地下咝咝作响的水能源在岛内的很多城市“破壳而出”，被储存在巨大的储水池内，为家居住宅、商行甚至是游泳池供热。火山喷发熔化了冰川形成河流，河水可通过涡轮为整个冰岛提供电力。

　　③即使如此，冰岛仍然决定更进一步进行能源更新改造，计划改装汽车、巴士和卡车，使用可再生能源作为燃料，不再依赖石油。他们已开始将水转化成燃料——氢燃料。具体转变过程如下：通过电极将水分解成氢分子和氧分子，氢电子穿过一种导体，产生电流，电流为电力发动机提供能量。氢燃料的成本目前是汽油的2到3倍，但效率却是天然气的3倍，总体成本实际上是一样的。更为重要的是，它不会产生碳污染，只形成水蒸汽。

　　④在首都雷克雅未克，他们已经对3款氢动力电力巴士进行了测试。驾驶员对此印象深刻。巴士司机劳格恩瓦尔杜尔·乔纳坦尔森说：“我更喜欢这些使用氢燃料的巴士，因为没有一点污染。”截止到本世纪中叶，所有的冰岛人都将被要求使用氢燃料汽车——到时候，汽油将在冰岛正式“下岗”。氢能源研究项目的玛丽·麦克说：“如果我们制造氢气并作为运输系统的燃料来使用的话，我们就可以让整个社会依靠自己的可再生能源运转。”冰岛人表示，他们会向世界证明通过电解水制造氢气的方式可以改掉过分依赖石油的习惯。——摘自2006年5月《科技博览》

1、冰岛不再使用汽油后，能源主要来自于哪两个方面呢？

　___________________________________________________

2、世界真奇妙，清水变成燃料！你知道冰岛人是怎样转变清水为燃料的吗？该燃料有什么优点？

　 过程：___________________________________________________

　 优点：___________________________________________________

3、“氢燃料的成本目前是汽油的2到3倍，但效率却是天然气的3倍，总体成本实际上是一样的。”该句主要运用了什么说明方法？其作用是什么？

　 说明方法是：_________________________________________________

　 其作用是：___________________________________________________

4、冰岛并不存在能源缺乏问题，但这个国家仍然努力成为世界上第一个不再使用汽油的国家。对此，你如何看？你还知道哪些像氢燃料这样的可再生、无污染能源呢？

　 我的看法：___________________________________________________

　 我还知道：___________________________________________________

I was blind, but I was ashamed of it if it was known. I refused to use a white stick and hated asking for help. After all, I was a teenager girl, and I couldn’t bear people to look at me and think I was not like them. I must have been a terrible danger on the roads, coming across me wandering through the traffic, motorists probably would have to step rapidly on their brakes. Apart from that, there were all sorts of disasters that used to occur on the way to and from work.

One evening, I got off the bus about halfway home where I had to change buses, and as usual I ran into something,“I’m awfully sorry,”I said and stepped forward only to run into it again. When it happened a third time, I realized I had been apologizing to a lamppost. This was just one of the stupid things that constantly happened to me. So I carried on and found the bus stop, which was a request stop, where the bus wouldn’t stop unless passengers wanted to get on or off. No one else was there and I had to try to guess if the bus had arrived.

Generally in this situation, because I hated showing I was blind by asking for help, I tried to guess at the sound. Sometimes I would stop a big lorry and stand there feeling stupid as it drew away. In the end, I usually managed to swallow my pride and ask someone at the stop for help.

But on this particular evening no one joined me at the stop; It seemed that everyone had suddenly decided not to travel by bus. Of course I heard plenty of buses pass, or I thought I did. But because I had given up stopping them for fear of making a fool of myself, I let them all go by. I stood there alone for half an hour without stopping one. Then I gave up. I decided to walk on to the next stop.

小题1:The girl refused to ask for help because she thought_________.

A．she might be recognized

B．asking for help looked silly

C．she was normal and independent

D．being fond blind was embarrassing小题2:After the girl got off the bus that evening, she_________.

A．began to run

B．hit a person as usual

C．hit a lamppost by accident

D．was caught by something小题3:At the request stop that evening, the girl___________.

A．stopped a big lorry

B．stopped the wrong bus

C．made no attempt to stop the bus

D．was not noticed by other people小题4:What was the problem with guessing at the sound to stop a bus?

A．Other vehicles also stopped there.

B．It was unreliable for making judgments.

C．More lorries than buses responded to the girl.

D．It took too much time for the girl to catch the bus.小题5:Finally the girl decided to walk to the next stop, hoping__________.

A．to find people there

B．to find more buses there

C．to find the bus by herself there

D．to find people more helpful there