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Fossil fuels are cheap, ______ they cause pollution.

What does the sign mean?

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Solar panels ______ electricity from sunlight.

Find the mistake in the following sentence.

We should using more renewable energy to protect the environment.

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There are ______ sources of renewable energy than non-renewable ones.

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______ source of energy is the source that can’t be replaced after use.

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Solar energy is ______ than fossil fuels.

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“Why is it called a ______ source?” – “Because it can be replaced easily and quickly.”