Casa · B1 Intermediate · Lesson 17 of 20 · Step 2

Science & Discovery

Scientific topics and advanced article usage

Use definite, indefinite, and zero articles correctly in advanced contexts
Understand when to use 'the' with unique nouns, superlatives, and specific references
Discuss scientific discoveries and processes

Words · tap a card to see it used

Grammar

Articles — a, an, the, zero article (advanced uses)

Use 'a/an' for first mention or non-specific singular countable nouns. Use 'the' for specific or previously mentioned nouns, unique things (the sun, the internet), superlatives, and with 'of' phrases (the University of Oxford). Use zero article for general plural or uncountable nouns (Water is essential), most country names, languages, meals, and academic subjects.

A scientist in Japan made an important discovery. The discovery was published in a leading journal.

The Earth revolves around the Sun.

Water is essential for life. (zero article — general statement)

She studies biology at the University of Melbourne.

Exercises · type, then check

1. Complete each sentence with 'a', 'an', 'the', or '—' (no article).

1. researchers at university have made important discovery.

2. Moon orbits Earth every 27 days.

3.She is studying chemistry because she wants to become scientist.

4.They published results in International Journal of Physics.

5. climate change is most serious challenge facing world today.

2. Choose the correct option to complete each sentence.

1. She works at ___ hospital in the centre of town.

2. ___ information in the report was very useful.

3. He wants to study ___ medicine after finishing school.

4. It was ___ best experiment we had ever conducted.

5. ___ scientists believe that ___ Mars may have had water.

0 of 10 answered · nothing you type leaves this device

Reading

A New Discovery in the Ocean

An international team of marine biologists has discovered a new species of fish in the Pacific Ocean. The fish was found at a depth of over 2,000 metres during an expedition led by the University of Hawaii. The species is unusual because it produces its own light — a phenomenon known as bioluminescence. Scientists believe the discovery could help them understand how life survives in the deepest parts of the ocean. Research on deep-sea creatures is still in its early stages. Much of the ocean remains unexplored, and experts say that thousands of unknown species may still be waiting to be found. The team plans to return to the area next year to continue their work.

1. What is unusual about the newly discovered fish?

2. Why do scientists think this discovery is important?

Speaking · say it out loud, with a partner or alone

1What is the most interesting scientific discovery you have heard about recently? Tell your partner about it.

2Do you think science will solve the world's biggest problems, such as climate change or disease? Why or why not?

Writing

Write 6–8 sentences about a scientific topic that interests you. Pay careful attention to your use of articles (a, an, the, or no article).

0 words

Finished?

Check your exercises first, then mark the lesson done.