Non-defining rel. clauses — What the Coral Reef Teaches Us
Grammar: Non-defining relative clauses
Free ESL grammar exercise on non-defining rel. clauses themed around what the coral reef teaches us. Printable worksheet from classplan.ai.
What's on this worksheet
A Level 4 (upper intermediate) ESL grammar exercise on science, practising non-defining relative clauses. The worksheet has a short reading excerpt, a grammar reference and graded practice items.
From the reading
The clownfish, which hides among the stinging tentacles of the sea anemone, cleans the anemone's tissue. Marine biologist Sylvia Earle, who has spent more than 7,000 hours underwater, calls the reef a masterclass in interdependence.
Grammar: Non-defining Relative Clauses
- Non-defining: who
- Used for people. Adds extra information between commas. Sylvia Earle, who has spent 7,000 hours underwater, studies coral reefs.
- Non-defining: which
- Used for things. The clause can be removed without changing the main meaning. The parrotfish, which grows to a metre, cleans the reef.
Sample items
- The Great Barrier Reef, ______ stretches for 2,300 kilometres, is the largest living structure on Earth.
- Sylvia Earle, ______ has logged more than 7,000 hours underwater, is one of the world's leading marine biologists.
- The parrotfish, ______ diet consists mainly of algae, keeps the reef clear and healthy.
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