1Britain has relatively few butterfly species compared with mainland Europe and 80% are in decline, mostly because intensive chemical farming has reduced many species to tiny fragments of habitat and small nature reserves.
主干主语：Britain；谓语：has；宾语：few butterfly species；并列分句主语：80%；谓语：are；表语：in decline
结构and 连接两个并列分句。前一分句含 compared with mainland Europe 作比较状语；后一分句 80% 承前省略 of butterfly species。mostly because 引导原因状语从句，从句主语 intensive chemical farming，谓语 has reduced，宾语 many species，to tiny fragments... 为介词短语作结果/程度状语。
译文与欧洲大陆相比，英国的蝴蝶种类相对较少，而且其中八成数量正在下降，主要是因为集约化化学农业已把许多物种压缩到零碎栖息地和小型自然保护区里。
考点and 并列分句中后句主语可承前省略 · because 原因从句中 reduce...to... 表示“使……沦为/缩减至”
2Butterflies may not pollinate as many plants as wild bees and hoverflies, but because British butterflies are the best-studied group of insects in the world, they are an extremely useful indicator of the wider declines in flying insects.
主干主语：Butterflies；谓语：may not pollinate；宾语：as many plants；转折后主语：they；谓语：are；表语：an extremely useful indicator
结构but 连接转折并列句。前句含 not as...as... 比较结构。后句中 because 引导原因状语从句，置于主句 they are... 之前；of the wider declines in flying insects 为介词短语修饰 indicator。
译文蝴蝶给植物授粉或许不如野蜂和食蚜蝇那么多，但因为英国蝴蝶是世界上研究最充分的昆虫类群，它们便成为衡量飞行昆虫整体衰退的极有用指标。
考点not as many...as... 同级比较的否定 · because 从句前置、主句 they 回指 British butterflies
3A children’s author and poet who had become a keen amateur photographer, Peters watched the butterflies and idly wondered if he could capture them in flight.
主干主语：Peters；谓语：watched / wondered；宾语：the butterflies / if 从句
结构句首 A children’s author and poet 为同位语，说明 Peters 身份；who had become... 为定语从句修饰 author and poet。主句两个并列谓语 watched 与 wondered；if 引导宾语从句，作 wondered 的内容。
译文身为儿童作家兼诗人、后来又迷上业余摄影的彼得斯，看着这些蝴蝶，不经意间想：自己能不能拍下它们飞翔的瞬间。
考点句首名词短语作主语同位语 · if 引导宾语从句表示“是否”
4A butterfly takes off so quickly it is still impossible to react quickly enough to capture that take-off but if he half-presses the shutter, the camera saves the 70 previous frames before the moment he actually takes the picture.
主干主语：A butterfly；谓语：takes off；并列后条件从句：if he half-presses；主句主语：the camera；谓语：saves；宾语：the 70 previous frames
结构so...that 结果结构中 that 省略（so quickly it is...）。but 连接转折。后半 if 条件状语从句，主句 the camera saves...；before the moment 为时间状语，he actually takes the picture 为省略关系词的定语从句修饰 moment。
译文蝴蝶起飞极快，人仍来不及反应去捕捉那一瞬；但若半按快门，相机会把真正按下快门前的七十帧保存下来。
考点so...that 中 that 可省略 · moment 后定语从句常省略 when/that
5As well as thousands of attempts, it takes patience and fieldcraft to anticipate a butterfly’s likely flight-line — and catch it — in focus.
主干形式主语：it；谓语：takes；宾语：patience and fieldcraft；真正主语：to anticipate...and catch it
结构As well as thousands of attempts 作附加状语，相当于 besides。it takes...to do 为形式主语结构。不定式 to anticipate...and catch it 为真正主语；破折号插入 and catch it，与 anticipate 并列；in focus 修饰 catch it。
译文除了成千上万次尝试，还需要耐心和野外功力，去预判蝴蝶可能的飞行路线——并把它拍实、对上焦。
考点it takes + 名词 + to do 表“做某事需要……” · as well as 置于句首表示“除……之外还”