Energy Sources

Respuesta correcta: A) exacerbate

• A) exacerbateCorrect. 'Exacerbate' means to make a problem or bad situation worse, which fits perfectly here.
• B) alleviateIncorrect. 'Alleviate' means to make something less severe, which is the opposite of what's needed.
• C) mitigateIncorrect. 'Mitigate' means to make something less severe, which doesn't fit the negative consequence implied.
• D) facilitateIncorrect. 'Facilitate' means to make an action or process easy or easier, which is not appropriate for a social divide.

Respuesta correcta: A) undermine

• A) undermine'Undermine' means to weaken gradually from below, and the sentence describes a subsidy that quietly works against the transition it claims to support.
• B) underline'Underline' means to draw a line beneath text for emphasis, and the clause is about weakening a policy rather than marking a page.
• C) overturn'Overturn' means to reverse a decision formally, and the sentence describes a slow structural effect rather than an annulled ruling.
• D) sustain'Sustain' means to keep something going, and the option would contradict the sentence, whose whole point is that the shift is hindered.

Respuesta correcta: A) accommodate

• A) accommodate'Accommodate' means to provide room for or adapt to, and the sentence states the opposite: the existing network has no capacity for the new generation.
• B) exaggerate'Exaggerate' means to represent as greater than it is, and the clause concerns physical capacity rather than an inflated claim.
• C) facilitate'Facilitate' means to make easier, and the sentence describes a constraint that blocks new connections rather than one that eases them.
• D) calculate'Calculate' means to determine numerically, and nothing in the sentence is about arithmetic or estimation.

Respuesta correcta: A) insulate

• A) insulate'Insulate' means to shield from something, and the sentence describes hedging by contract: long-term buyers are protected from the rise in spot prices.
• B) inspire'Inspire' means to arouse enthusiasm or creativity, and the clause is about financial exposure rather than motivation.
• C) insure'Insure' would mean to cover against loss under an insurance contract, which is a different arrangement from buying fuel at a fixed price.
• D) instil'Instil' means to put a quality into someone gradually, and the clause describes a financial shield rather than a transmitted habit.

Respuesta correcta: C) Solar panels on schools reduced costs and became a learning tool.

• A) The schools no longer use any electricity from the grid.Incorrect. The text says that on cloudy days 'the schools still use electricity from the grid'.
• B) The project was cancelled because it was too expensive.Incorrect. The project was completed, and the city plans to add ten more schools, so it was not cancelled.
• C) Solar panels on schools reduced costs and became a learning tool.Correct. The text explains the 40 per cent saving, how the money is reused and how teachers use the panels in science classes.
• D) Students must repair the solar panels in their science classes.Incorrect. Students observe the energy production on a screen; the text never says they repair the panels.

Respuesta correcta: B) Small community projects can also produce energy without damaging nature much.

• A) Big hydroelectric dams are always illegal in Colombia.Incorrect. The writer never talks about the legality of dams; the sentence compares the size of projects, not laws.
• B) Small community projects can also produce energy without damaging nature much.Correct. The writer describes a small plant with no dam, stable power for twenty families and an unchanged stream, so the final sentence suggests that small projects are a valid alternative.
• C) The village should disconnect from the national grid.Incorrect. The writer does not propose leaving the grid; the micro-plant solved the problem of unstable power.
• D) Micro-hydroelectric plants kill all the fish in a stream.Incorrect. The writer says 'The fish are still there', which contradicts this option.

Respuesta correcta: D) Because dirty filters make the air conditioner use more energy.

• A) Because clean filters lower the temperature to 24 degrees.Incorrect. 24 degrees is the recommended setting chosen by the user; the text does not connect it with cleaning filters.
• B) Because the electricity company will check them every month.Incorrect. The guide does not mention any inspection by the company; it gives advice to families.
• C) Because dirty filters are the reason why inverter models are expensive.Incorrect. The higher price of inverter models is a separate point; it has nothing to do with dirty filters.
• D) Because dirty filters make the air conditioner use more energy.Correct. The guide says to clean the filters 'because dirty filters make the machine work harder', which means more electricity consumption.

Respuesta correcta: A) To support electric buses while reminding readers that the energy source also matters.

• A) To support electric buses while reminding readers that the energy source also matters.Correct. The writer praises the buses ('the city is right to be proud') and then adds a reservation about where the electricity comes from, summarised in the last sentence.
• B) To argue that Bogotá should return to diesel buses.Incorrect. The writer calls electric buses 'a great step'; nothing suggests returning to diesel.
• C) To explain how hydroelectric plants produce electricity.Incorrect. Hydroelectric plants are mentioned as a source, but the text does not explain how they work.
• D) To complain about the noise of the new buses.Incorrect. The writer says the buses are quiet, which is presented as an advantage.

Respuesta correcta: D) a process in which communities are asked for their opinion before a project begins.

• A) a medical appointment for workers before they build turbines.Incorrect. 'Consultation' can mean a visit to a doctor, but here it refers to communities and projects, not health.
• B) a payment that communities give to the companies.Incorrect. The text mentions agreements that give jobs and water to communities, not payments from them.
• C) a report written after the wind farm has been built.Incorrect. 'Prior' means before; a report written after construction is the opposite of what the phrase describes.
• D) a process in which communities are asked for their opinion before a project begins.Correct. 'Prior' means before, and the text says the consultation must happen 'before starting a project' with each affected community.

Respuesta correcta: C) Register online, because places are limited.

• A) Pay an entry fee at the main square.Incorrect. The message clearly says 'Entry is free'; no payment is mentioned.
• B) Bring their own solar panel to the fair.Incorrect. Students will build a small solar charger at the fair; they are not asked to bring a panel.
• C) Register online, because places are limited.Correct. The message says that to join the workshop 'you must register online because there are only 30 places'.
• D) Arrive before 10 a.m. to get a place.Incorrect. The fair starts at 10 a.m., but places in the workshop are obtained by online registration, not by arriving early.

Respuesta correcta: B) had

• A) hasIncorrect. The sentence refers to a past sequence, requiring the past perfect in inversion.
• B) hadCorrect. 'Hardly had...' is a classic C1 inversion structure used for sequential events.
• C) wasIncorrect. 'Was' does not fit the past perfect structure required by 'Hardly'.
• D) didIncorrect. 'Did' would require the base form of the verb, not the past participle 'been'.

Respuesta correcta: B) did

• A) had'Not until' inverts the main clause, placing the auxiliary before the subject 'the household'. 'Had the household seen' would leave the subject first, which the pattern forbids.
• B) did'Not until the turbines were connected did the household see'. The auxiliary is fronted to invert the clause, which is the defining feature of the structure.
• C) was'Was' would suggest a passive or a singular subject. The subject is singular but the verb is active, so a passive reading is not available.
• D) do'Do' is present tense and cannot invert a past sequence in which the connection had already been completed.

Respuesta correcta: C) The writer acknowledges an environmental benefit while introducing a separate land-use concern.

• A) The writer claims that low-carbon electricity directly causes residents to lose their farms.The statement expresses a concern about land use; it does not establish a causal claim or say that farms will be lost.
• B) The writer concludes that residents have no concerns about the project.The main clause explicitly states that residents are concerned, so this interpretation contradicts the text.
• C) The writer acknowledges an environmental benefit while introducing a separate land-use concern.'Although' concedes the benefit of low-carbon electricity while the main clause presents a contrasting concern about farmland.
• D) The writer presents the farmland concern as proof that solar electricity has high carbon emissions.Land-use effects and carbon emissions are different issues; the statement explicitly describes the electricity as low-carbon.

Respuesta correcta: A) Although the wind farm produces electricity without burning fuel, its output varies with wind conditions.

• A) Although the wind farm produces electricity without burning fuel, its output varies with wind conditions.'Although' can introduce a clause with a subject and finite verb, preserving the contrast between fuel-free generation and variable output.
• B) Despite of the wind farm produces electricity without burning fuel, its output varies with wind conditions.'Despite of' is not the standard construction, and 'despite' cannot directly introduce this finite clause.
• C) In spite the wind farm produces electricity without burning fuel, its output varies with wind conditions.The expression requires 'in spite of' followed by a noun phrase or gerund construction, not this directly attached finite clause.
• D) Because the wind farm produces electricity without burning fuel, its output varies with wind conditions.'Because' changes the contrast into a causal claim, incorrectly making fuel-free generation the reason for variable output.

Respuesta correcta: C) A difference in the land requirements of the two proposed installations.

• A) A sequence in which rooftop panels must be installed before the ground-mounted array.'By contrast' marks a difference, not a time sequence; neither sentence specifies an installation order.
• B) A reason why rooftop panels always generate more electricity.The comparison concerns installation space and gives no information about how much electricity either system generates.
• C) A difference in the land requirements of the two proposed installations.The connector highlights existing rooftop space versus a separate plot of land, making land requirements the point of comparison.
• D) A similarity showing that both installations require a new plot of land.The rooftop proposal uses existing buildings, so the text distinguishes rather than equates their need for additional land.

Respuesta correcta: D) does

• A) do'Do' agrees with plural subjects, and 'a national grid' is singular, so the base form with 'does' is required.
• B) have'Have' would give the perfect aspect, but the bare inversion with 'rarely' and a singular subject takes 'does' before the base form.
• C) are'Are' would be needed for a plural subject. 'A national grid' is singular, and the negative adverbial does not alter agreement.
• D) does'Rarely does a national grid adapt'. The singular subject takes 'does' and the main verb reverts to the base form 'adapt'.

Respuesta correcta: B) The current strategy is directed towards the wrong objective.

• A) They are literally looking for something in the trees of Cali.Incorrect. This reads the idiom word for word; nobody in the debate is searching any trees, because the phrase is figurative and describes a mistaken strategy.
• B) The current strategy is directed towards the wrong objective.Correct. 'Bark up the wrong tree' comes from hunting dogs barking at a tree the animal is not in, so it means putting effort into the wrong cause or the wrong solution.
• C) The approach is too noisy and aggressive.Incorrect. 'Barking' here does not describe loud or aggressive behaviour; the idiom is about aiming at the wrong target, not about the tone of the discussion.
• D) A new environmental project involving trees should be started.Incorrect. The speaker is criticising the current approach, not proposing a new project; 'tree' is part of a fixed expression and has no literal meaning here.

Respuesta correcta: B) Test the dryer to see how well it works.

• A) Throw the dryer away because it failed.Incorrect. Carlos says it works in the lab, and Isabel wants to test it more, not get rid of it.
• B) Test the dryer to see how well it works.Correct. 'Try something out' means to test it in practice; she wants to check its performance 'in real conditions' on a farm.
• C) Take the dryer outside the lab only for a photo.Incorrect. 'Out' here is part of the phrasal verb meaning to test; a photo would not show if the dryer 'really works'.
• D) Sell the dryer to coffee farmers immediately.Incorrect. She says they won't know if it really works yet, so selling it now would contradict her caution.

Respuesta correcta: D) Acknowledging Manuela's reasons before presenting a different view.

• A) Asking Manuela where she lives.Incorrect. 'Where you're coming from' refers to someone's reasons or point of view, not to a place.
• B) Agreeing completely that oil exploration should stop today.Incorrect. He adds 'We need a plan for them first', which means he does not want to stop immediately.
• C) Saying that climate change is not a real problem.Incorrect. He never denies climate change; his concern is the economic effect on families.
• D) Acknowledging Manuela's reasons before presenting a different view.Correct. 'I see where you're coming from' shows that he understands her reasons, and 'but' introduces his objection about families who depend on oil income.

Respuesta correcta: A) Old fridges consume a large amount of electricity.

• A) Old fridges consume a large amount of electricity.Correct. 'Eat up' means to use a large quantity of something; he suggests the old fridge may explain the higher bill.
• B) The old fridge has food that has gone bad.Incorrect. This takes 'eat' literally; he is talking about energy consumption, not food.
• C) Gloria should buy more food for her fridge.Incorrect. Hernán does not give advice about food; he gives a possible reason for the high bill.
• D) Old fridges use less energy than new ones.Incorrect. This is the opposite of his point; he blames the old model for consuming a lot.