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Language study: Cause and effect.

Study these pairs of actions, what is the link between each pair?
1. The gas expands.
2. This drives the piston down.
3. The piston ascends.
4. This forces the products of combustion out.

There are two links between the actions:
They happen at the same time. We can show this using As

1+2 As the gas expands, it drives the piston down.
3+4 As the piston ascends, it forces the product of combustion out.

One is a cause and the other is an effect.
1 Cause: The gas expands.
2 Effect: This drives the piston down.
3 Cause: The piston ascends.
4 Effect: This forces the products of combustion out.

We can show both the time link and the cause and effect link like this:
1+2 The gas expands, driving the piston down.
3+4 The piston ascends, forcing the products of combustion out.

Step 5

Link these actions in the same way.
Cause Effect
1.The piston moves down This creates a partial vacuum.
the cylinder.
2.The piston creates a This draws in fuel from the
vacuum. carburetor.
3.The piston moves up the This compresses the mixture.
cylinder.
4.The gas expands quickly. This pushes the piston down.
5 The piston moves up and This rotates the crankshaft.

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