I. Grammar

unpacking complex sentence

Appositives are often punctuated by commas.

• commas → the information is optional = the sentence still grammatically correct without them

• remove or set aside the appositives → clearer overall meaning of the sentence becomes →examine separately the additional details added by the appositives.

Examples:

Look at the sentence from the passage The Eiffel Tower and unpack this complex sentence.

The Crystal Palace, made of iron, erected for the 1851 Great Exhibition in London, covers the largest area; the Brooklyn Bridge, completed in steel in 1883, has the longest span; and the Eiffel Tower, made of steel and started in 1887, reaches the greatest height.

You can rewrite it in a diagram like this: