化学反应的实质就是旧键的断裂和新键的生成，欲探讨发生化学反应时分子中化学键在何处断裂的问题，近代科技常使用同位素示踪原子法，如有下列方法：

2R﹣¹⁴CH=CH﹣R′​R﹣¹⁴CH=CH﹣R+R′﹣¹⁴CH=CH﹣R′

由此可以推知：化合物反应时断裂的化学键是（　　）

    Ten years ago I used to be very fit. I rode a bike to work and I got a lot of exercise at weekends. I used to play tennis a lot and go for long walks. In those days I didn't earn very much. I had a job in an office. It wasn't a very good job but I had a lot of time to do the things I enjoyed.

    Then, about eight years ago, I got a much better job. The pay was better, but the hours were a lot longer. I bought a car and drove to work every day. I began to take people out for lunch. And I began to put on weight, too. I stopped playing tennis and going for long walks at weekends because I just didn't have any time for things like those any more.

    There was a lot of stress in my job. Perhaps that was why I started drinking more than I used to. For example, I used to have only half a glass of whisky when I got home, but then I started filling my glass to the top, and instead of having one glass, I would have several. I started smoking a lot, too. I never used to smoke at all.

    Two months ago I had a heart attack. At first I just couldn't believe it. Luckily it wasn't very serious. The doctor advised me to stop smoking and to eat less. He also advised me to work less and get more exercise. But I just haven't got any time! My job takes everything out of me!

    Sometimes I wonder if I should get another job. Perhaps I could do something as I used to. But if I do that, I won't earn as much. I have a family to support. I have to think of them, too. I just don't know what I should do. What do you think?

逢故人

杜牧

年年不相见，相见却成悲。

教我泪如霰，嗟君发似丝。

正伤携手处，况值落花时。

莫惜今宵醉，人间忽忽期。

①若烃与H₂完全加成反应时的物质的量之比为1：3，它是．

②若烃与H₂完全加成反应时的物质的量之比为1：2，它是．

③苯乙烯与H₂完全加成的物质的量之比为．

    When I was in Germany, one day at Christmas-time I went to a post office to send a letter. To my 1, I found people queuing some paces away from the 2 at the savings deposit (存款) window.

    Why so? Each did his business in turn but the line never 3 a step nearer .I was very curious, so I walked to the window to 4 the cause. There was a 5on which was written “ Thank you for your respect for other's privacy”—a polite 6 to keep people away from nosing into other's affairs (money matters are regarded as privacy in Western countries). I was deeply 7 by the sight and stayed a while to watch: they were 8 so calmly at a distance that they seemed quite 9 to the practice. The 10 thing happened at a public telephone box. Those waiting for their 11 always kept their distance—enough to be out of 12. It's another typical example! From then on I 13 to watch their ways of doing things, manners, treatment shown towards 14. I found the Germans always mindful of other's privacy（隐私）. They 15 not to put others in an embarrassing (窘迫) situation. For instance, they never 16 about age, incomes or the place to buy such a coat, nor would they talk about the others or 17 others wore on their necks. Their laws 18 reading diaries or opening letters without 19. It's obvious that it shows 20 matters are not allowed to be disturbed.

流淌的秋虫清音

付秀宏

中秋是一个丰收的时令，听秋虫在秋夜里声声鸣叫，仿佛是听孔子讲不舍昼夜，听峨眉山的法师讲解禅心，让我的内心变得阔远，因着秋凉的沉静被洗涤，像似秋空和秋水一样。

中年的我，有几年很是热衷法布尔的《昆虫记》，可惜此后，除了听到秋光里蟋蟀的凄清鸣叫，闻到蜻蜓飞过头顶的草色醇香，对那些细小的生灵，我几近相忘。虽然很长时间没有读法布尔，但我还是记得那个法国长寿老头的昆虫王国。

秋虫，就像秋天一样，辽阔中交融着丰富与淡然、喜悦与凄凉，那种难以言明的情绪总在心头萦绕。

一位朋友曾捉到蹲伏在厨房角落里的一只瘦小的蟋蟀，因为惊惧，它的清脆而响亮的声音戛然而止。朋友和我提起此事，我笑着说，你打扰蟋蟀作诗了。

蟋蟀是唐朝的李白，黑夜是它饮不完的酒。噫!秋虫与秋夜之相悦，是把深情写在纸上的那种感觉。

前两天去母亲家，住在那里。窗外的一棵小樱桃树下，秋虫不停歇地吟唱，我不知道哪一声鸣叫是海子的，哪一声又是北岛的，密密匝匝的樱桃叶子看过去一是无数沉醉的耳朵。

还曾读过一首有关秋虫的诗歌，题目叫《为何不带秋虫回家》，我臆测这里的“家”是人的心灵的家园。你想啊，秋虫的诗会多像李清照的诗词专场，它可以把人们一颗颗浊躁的心变得一点一点清澈起来。难怪有人说，彻夜的虫鸣好比山顶银河倾泻的水，洗涤着那些仰望天空的人们……

秋虫就是禅修的一种，虽然细微，但非常沉醉迷人，即便有些冷寂，但那种专注、那种深情，可以让人的身心澄明起来，那是秋的暗语与玄机。一鸣三千里，都写在一个人又一个人的心弦上，恰似“海上生明月，天涯共此时”的境界。

秋虫有清音，它们不嘲笑什么，只是把生命里低沉的基音和高亮的泛音用断续的咏叹表达出来。秋虫清音的高与低，唱与停，融汇在秋空的高渺与周遭的宁静里……的确，只有这种微小的生命才能发出这样的声音，那是一群执着灵魂的美妙合唱。

记得，幼时对静寂之声敏感。那秋虫、那鸣叫、那声韵，还有那种说不清的凄凄切切，每晚悠扬动人地响着，令我异常着迷。从立秋开始，秋虫们日复一日踩着灼热夏季的尾巴，把秋意谱成深夜里长长的弦歌；在明耀的新月下或徐缓的凉风中，有意无意地靠着枕，听虫儿们的合奏，足以撼动泪湿的心情。这种种心迹，现在回忆起来，那份亲切似乎与年俱增了。

对秋虫的声音，何以如此钟爱呢？难道说它们的演奏是一川清凌凌的融水？是啊，秋虫的清音，在自然中汇入了无尽的神妙，于是众妙毕集，各抒灵趣，我自己也有点儿说不清道不明。反正，每当没听到秋虫之声，便会莫名地想流泪，生出难于言说的慰藉与寂寥。我的心情，仿佛远离了床榻，沉浸在思慕与怀恋之中。这些虫声里会有李白的感叹、杜甫的伤怀、李商隐的微唱、李煜的低泣，酸酸麻麻的，却有非常永恒的心境。

夜沉沉地睡了，只有往昔真挚而柔韧的声音，宛若秋水的微澜一般颤动不已。我不能忘怀于秋虫之鸣，任由秋虫是先哲心声余韵那般缭绕着，似动不动，似淌非淌，用它不懈的努力——融化我敏感多愁的心。听得久了，我如同羁旅返乡的游子终于踏上故土，又似忆起与诗心碰撞那一刻的会心之笑，既有几分陌生，又感到舒畅和亲切。因有秋虫在耳，自己的情感得以恢复本来的纯净。

不知多少次，半夜从睡梦中醒来，听见秋虫的哨子还在奏响，只是有一点儿瑟瑟的冷意。当这凉意微逗之时，我心中总是疑惑：这是不是“纷披灿烂”的《广陵散》遗篇？是不是唐末黄巢《不第后赋菊》的“我花开后百花杀”？这时，我的心——像夏日河面上的巨蜻蜓时停时飞，惊骇般地睁大了眸子。从一个文化记忆驶向了另一个桥头，犹如驶入了梦境；夜半秋虫清音——于我，仿佛是一个个的新发现，引发深切的共鸣。

秋天气温日渐降低，虫音那冷静而又清澈的质感，如秋月般洁白纯净，如月光般水银泻地，如秋风般凉意深沉，亦如秋风般了无痕迹。听秋虫之声，最有情味，如同古老编钟一样传来的悠远的音。那悠悠的声音仿佛有了倒影似的，一身静气地走着，值得我们去用心细细品味。如果有雅兴，不妨披一件夹袄，一个人走进这秋野之夜，此间月光清亮、露水清凉，虫鸣清越而密集，蟋蟀、蝈蝈、金铃子的清音一起倾倒而来，却丝毫不纷乱，婉转缠绵，喃语不尽。我甚至能察觉到，家中秋虫的低吟浅唱，已与明月之下田野里的噪噪天籁，交相共鸣，合成了一处旋律。

我不禁潸然泪下，倘若此时有人问我：“秋虫的声音如何迷人？”我会静静地说“在这声音中，不仅领悟到各种美妙的声音，而且可以听懂你自己。”因声声不息的秋虫清音，能把自己的那颗心读懂、读透，该是身为人最幸福的事情了!

(摘编自《人民周刊》2020年18期，有删减)

The bed.