Giáo án Looking back

Ss recall the unit topic and the two participle forms they studied in Unit 5.

T writes three sentences on the board:

• Burning fossil fuels, factories release carbon dioxide.
• Heated by sunlight, the surface warms.
• Working together, we can act faster.
  Ss look at each first word (ending in -ing or -ed) and decide whether the clause has an active or a passive meaning.

Ss identify that 'Burning fossil fuels' is an active participle clause (the factories burn fuel), 'Heated by sunlight' is a passive participle clause (the surface is heated), and 'Working together' is an active clause (the same we work). Ss name the topic: global warming and climate change.

Ss review the form and meaning of present- and past-participle clauses, and check the meaning by expanding each clause into a full clause.

Ss read the grammar box on the slide:

• A present-participle clause usually has an active meaning: Burning fuel, the engine releases gases.
• A past-participle clause often has a passive meaning: Heated by sunlight, the surface warms.
• The understood subject must match the main-clause subject; avoid dangling participles.
  Task 1: T asks Ss to expand the two examples. Task 2: T asks Ss to find the dangling participle among: 'Walking to school, Lan noticed the smoke.' and 'Walking to school, the smoke worried Lan.'
  Guiding questions:
• 'Who is burning the fuel in the first example?'
• 'Who is walking in the second sentence? Is the smoke walking?'
• 'Does the expanded clause show a reason, a time or a related action?'

Ss expand the examples correctly:

• 'Burning fuel, the engine releases gases.' → 'When it burns fuel, the engine releases gases.' (time/related action)
• 'Heated by sunlight, the surface warms.' → 'When it is heated by sunlight, the surface warms.' (time/reason)
  Ss choose 'Walking to school, Lan noticed the smoke.' as the correct sentence, because Lan is both walking and noticing. Ss state the rule in one sentence: 'The understood subject of a participle clause must be the same as the subject of the main clause.'

Ss review and use the six key words of Unit 5 correctly in meaningful contexts.

Ss complete Worksheet No. 2, matching each term with its Vietnamese meaning:

• greenhouse gas, emission, black carbon, fossil fuel, mitigation, climate
  Then Ss read the sentence: 'Burning fossil fuels increases greenhouse-gas concentrations, while incomplete combustion can produce black carbon.' T asks: 'Is black carbon the same as carbon dioxide?'

Ss match the words correctly:

• greenhouse gas = khí nhà kính
• emission = phát thải
• black carbon = cacbon đen
• fossil fuel = nhiên liệu hoá thạch
• mitigation = giảm nhẹ
• climate = khí hậu
  Answer to T's question: 'No. Black carbon is a component of soot, not another name for carbon dioxide.'

Ss recognise how content words receive stress, how contrast shifts emphasis, and how unstressed words remain clear.

T shows the model sentences:

• Burning FOSSIL FUELS releases CARBON DIOXIDE.
• We need CLEANER ENERGY, not just a NEW SLOGAN.
  T reads each sentence aloud twice: first slowly, then at a natural pace. T explains that content words form the beats, and that contrast can move the emphasis. Ss repeat in chorus, then individually.
  Guiding question: 'Why is 'cleaner' stressed in the second sentence? What does the stress on 'slogan' show?'

Ss say that the stress on 'cleaner' focuses on the kind of energy we need, while the stress on 'slogan' contrasts words with real action. Ss read both sentences with a clear rhythm: content words stressed, function words light but audible (for example 'we', 'need', 'not', 'just', 'a').

Ss choose the correct participle form and the sentence without a dangling participle, using the meaning of the clause.

Ss complete Worksheet No. 1 individually in five minutes. Then they check their answers in pairs. Items 1–8 are multiple-choice questions taken from the unit's practice set. Ss must give a reason for each choice, based on the meaning of the clause.

Answer key for Worksheet No. 1:

1. C – Burning fossil fuels, factories release carbon dioxide. (Factories actively burn fuel.)
2. B – Filled by smoke, the room became difficult to use. (The room receives the filling: passive meaning.)
3. A – Walking to school, Lan noticed the smoke. (Lan is both walking and noticing.)
4. D – Understanding the risks, the team changed its plan. (The team actively understands.)
5. C – Seen from the road, the field looks dry. (The field is seen, not doing the seeing.)
6. B – Hoping to reduce waste, students reused the boxes. (Students are the people hoping.)
7. A – Damaged by the storm, the bridge was closed. (The bridge receives damage.)
8. D – Working together, we can act faster. = If we work together, we can act faster. (The same we performs both actions; the clause expresses a condition.)

Ss use participle clauses, topic vocabulary and sentence stress to write a short, accurate text for a school information stand.

Working in groups of four, Ss draft a short text (three to four sentences) for an information stand. The text must explain one mechanism and one feasible action:

• Mechanism: burning fossil fuels increases greenhouse-gas concentrations; incomplete combustion can produce black carbon.
• Feasible action: reducing unnecessary vehicle idling through the school's authorised arrangements.
  The text must include at least two participle clauses and must distinguish a proposed action from a measured reduction. Ss also note that a science teacher should check the source notes, and that no waste will be burnt for a demonstration; a drawing can be used instead.

Each group produces a draft text on the A4 sheet. A model draft:

• 'Burning fossil fuels increases greenhouse-gas concentrations. Produced by incomplete combustion, black carbon is a component of soot, not carbon dioxide. We propose reducing unnecessary vehicle idling through the school's authorised arrangements. Measured reduction will need evidence, such as monitoring records, before we can claim progress.'