In July（七月）/ˌʤuˈlaɪ/, Nora joined a weekly（周刊）/'wi:kli/ field course at Silent Marsh. Eighty（八十）/ˈeɪti/ young（年幼的）/ˈjʌŋɡə/ volunteers came, but swimming（游泳）/sˈwɪmɪŋ/ was banned regardless（不管）/ri'gɑ:dlis/ of the warmth（温暖）/wɒ:mθ/. Their actual（真实的）/'æktʃuәl/ difficulty（难点）/ˈdɪfɪˌkəlti/ was the separation（分离）/.sepә'reiʃәn/ of ordinary seasonal change from industrial pollution. A new development（开发项目）/dɪˈvɛləpmənt/ stood beyond a line of pine（松树）/pain/ trees, and an airplane（飞机）/ˈɛrˌpleɪn/ crossed overhead as Dr Patel asked everyone to judge the water by evidence, not by casual（偶然的）/'kæʒjuәl/ belief.

Each pair received a clean container, an oxygen（氧）/'ɒksәdʒәn/ meter（米）/'mi:tә/, and strict criteria（pl. 标准）/krai'tiәriә/ for sampling. Nora took a handful of mud（泥）/mʌd/ and watched a frog（青蛙）/frɑg/ disappear beneath the clay（泥土）/klei/. Back in the laboratory（实验室）/ˈlæbrəˌtɔri/, she used a microscope（显微镜）/'maikrәuskәup/ to compare a typical（典型的）/'tipikl/ plant cell（细胞）/sɛl/ with an abnormal one. The water contained acid（酸）/'æsid/, an unknown chemical（化学药品）/'kemikl/, and too much dioxide（二氧化物）/dai'ɒksaid/. Its mineral（矿物）/'minәrәl/ balance was unusual, so the roots could not absorb（吸收）/әb'sɒ:b/ enough oxygen.

A local saleswoman（女售货员）/'seilzwumәn/ named Mara supplied the next clue（线索）/klu:/. She had seen a drunk（喝醉了的）/drʌŋk/ visitor drop a cigar and several cigarette（香烟）/.sigә'ret/ ends beside a pipe that seemed to suck（吸）/sʌk/ dark liquid from the factory. “I may sound somewhat（某物）/'sʌmhwɒt/ dramatic, but I sincerely（真诚地）/sin'siәli/ think that pipe is the core of the problem.” Nora acknowledged the possibility（可能性）/ˌpɑsəˈbɪləˌti/ but would not accuse anyone before a systematic（有系统的）/.sisti'mætik/ test qualified（取得资格）/'kwɒlifai/ as proof.

The second sample revealed protein from food waste and the shell of a nut（坚果）/nʌt/, while a creature（人）/'kri:tʃә/ that residents called the “marsh beast（畜生）/bi:st/” proved to be a large fish. The team began to perceive（感觉）/pә'si:v/ local stories differently, but its concern about extinction（消失）/ik'stiŋkʃәn/ remained. Nora used a standard technique（技巧）/tɛkˈnik/ to sort（分类）/ˈsɔːtɪŋ/ a variety（多样性）/vəˈraɪəti/ of samples beside a numbered pole（杆）/poʊl/. A wrinkle（皱纹）/'riŋkl/ in one label forced her to refer to（查阅）/refer to/ the field notes again. That unique（独一无二的）/ju:'ni:k/ correction helped the data qualify for comparison（比较）/kәm'pærisn/. Old records then showed how the wetland's primitive（原始人）/'primitiv/ ecosystem had changed through both natural evolution（进化）/.i:vә'lu:ʃәn/ and human pressure. The evidence was specific enough to defend a demand for reform（改革）/rɪˈfɔrm/.

At the final meeting, Dr Patel said, “Ask yourself（你自己）/ˈjɔrsɛlf/ what a living being（存在）/'bi:iŋ/ needs before you suggest a solution.” Nora proposed better waste treatment and a safe recreation（娱乐）/.rekri'eiʃәn/ path. The council offered official recognition（赞誉）/.rekәg'niʃәn/ and accepted the plan. The result was not a stroke of fortune（财富）/'fɒ:tʃәn/: it came from patience, method, and motivation（动机）/.mәuti'veiʃәn/. Nora felt relief, yet also sorrow for the damaged marsh. The project had taught her to regard field science as work with a soul（灵魂）/sәul/.