This is a persuasive text — most likely a column or opinion piece — arguing that official reassurances about a river's recovery are not to be trusted. Its persuasion is achieved very largely through GRAMMATICAL and SYNTACTIC choices: a calculated contrast between the passive, agentless voice of officialdom and the active, imperative voice of first-hand witness, reinforced by sentence function, modality and parallelism. The grammar does not decorate the argument; it IS the argument.
The opening paragraph ventriloquises the official position, and the writer uses VOICE to discredit it. 'You are told that the river is recovering' and 'The figures, we are assured, are improving' are both PASSIVE constructions with the agent deleted: told by whom? assured by whom? This agent deletion makes the reassurance sound faceless and institutional, and — crucially — unaccountable. The third sentence, 'Trust, they say, the process', finally supplies an agent, but only the vague, dismissive pronoun 'they', which positions the official voice as a shadowy, untrustworthy collective set against the reader's 'you'. The fronting of the imperative 'Trust' before its object ('Trust… the process'), with the interruptive 'they say', also lets the writer quote the instruction while audibly mocking it.
The second paragraph executes a deliberate grammatical TURN, and the hinge is the conjunction 'But'. The writer abandons the passive entirely and switches to a run of IMPERATIVES — 'walk the bank', 'See the grey scum', 'Smell what no report can sanitise', 'ask yourself'. This shift in sentence FUNCTION from declarative report to direct command does two things: it seizes authority (the writer now instructs the reader, as the officials did, but on the basis of sensory evidence), and it pulls the reader bodily into the scene, making them a witness rather than a recipient of figures. The imperatives are also active and agentive — YOU are to act, see, smell — the precise opposite of the agentless passives that opened the text. Voice and mood together stage a contest between hearing and seeing, between being TOLD and finding out.
Syntactic patterning sharpens the appeal to the senses. The parallel imperative structure 'See the grey scum… Smell what no report can sanitise' uses anaphora-like repetition of sensory verbs in initial position to build a rhythm of accumulating evidence, while the concrete noun phrase 'the grey scum that coils against the reeds' — with its relative clause and the sinister dynamic verb 'coils' — stands in pointed contrast to the bloodless abstract nouns of the first paragraph ('figures', 'process'). The grammar of the two paragraphs is thus opposed at every level: passive vs active, declarative vs imperative, abstract vs concrete.
The text culminates in a single long INTERROGATIVE that gathers the whole argument: 'if the river were truly healing, would it need quite so many people, quite so insistently, to keep telling you so?' This is a complex sentence opening with a SUBJUNCTIVE conditional ('if the river were truly healing'), whose hypothetical mood implies that it is NOT healing. The rhetorical question, by its function, compels the reader to supply the writer's own answer. The parallel adverbial phrases 'quite so many people, quite so insistently' use repetition and modality ('quite so') to insinuate that the very INSISTENCE of the reassurance is evidence of its falseness — the more they protest, the less we should believe them.
In sum, the text persuades by orchestrating grammar: agent-deleted passives to discredit officialdom, a conjunction-hinged turn to active imperatives to enthrone first-hand witness, sensory parallelism and concrete syntax to make the evidence vivid, and a subjunctive rhetorical question to seal the doubt. The reader is positioned, through sentence after sentence, to trust the active, seeing, commanding 'I/you' of the writer over the passive, faceless 'they' of the report — a reception entirely engineered at the level of syntax.