---
title: "English C-Test B2: Citizen science · C-Test Prep"
description: "Free English C-Test at B2 level: \"Citizen science\", 25 gaps to fill in and check online, with the answer and an explanation for every gap."
canonical: https://ctestprep.de/en/c-test-english-exercises/b2-citizen-science
last_updated: 2026-10-31
---

# English C-Test B2: Citizen science

An English C-Test at B2 level: longer sentences with clauses and the passive, topics from study and society.

Last checked: 31 October 2026

25 gaps: 14 on grammar, 11 on vocabulary. Complete the second half of each word, then check; every answer with its explanation is under the text.

## Citizen science

B2

Science is usually done by professionals, but some research projects depend on help from thousands of ordinary people. In th___ citizen sci___ projects, volun___ count bi___ in th___ gardens, rec___ when t___ first flo___ appear i___ spring o___ measure t___ quality o___ water i___ streams. Oth___ sort ima___ on th___ computers a___ classify gala___ that ha___ been photog___ by teles___. Because amat___ make mist___, several peo___ check ev___ image. In this way, researchers collect far more data than a small team could ever gather, and some volunteers have even discovered unusual objects that professional astronomers had overlooked.

### Answers and explanations: Citizen science

1. these Grammar
   "these projects": "these" (plural of "this") points back to the projects just mentioned.
2. science Vocabulary
   "citizen science" = research done with the help of the public.
3. volunteers Vocabulary
   "volunteers" = people who help without pay.
4. birds Vocabulary
   "count birds".
5. their Grammar
   "their gardens", "their computers": possessive for the volunteers (plural).
6. record Vocabulary
   "record" = write down (a verb here).
7. the Grammar
   "the first flowers" (ordinal number), "the quality of water" (defined by "of").
8. flowers Vocabulary
   "flowers" = the coloured parts of plants.
9. in Grammar
   "in spring" (season), "in streams" (place).
10. or Grammar
    "or" adds the last option in a list.
11. the Grammar
    "the first flowers" (ordinal number), "the quality of water" (defined by "of").
12. of Grammar
    "the quality of water".
13. in Grammar
    "in spring" (season), "in streams" (place).
14. Others Grammar
    "Others" = other volunteers; a pronoun without a noun.
15. images Vocabulary
    "images" = pictures.
16. their Grammar
    "their gardens", "their computers": possessive for the volunteers (plural).
17. and Grammar
    Conjunction joining two parts of equal rank.
18. galaxies Vocabulary
    "galaxies", plural of "galaxy" (y → -ies).
19. have Grammar
    "have been photographed": present perfect passive; "have", because "galaxies" is plural.
20. photographed Grammar
    Past participle of "photograph" in the passive.
21. telescopes Vocabulary
    "telescopes" = instruments for looking at distant objects.
22. amateurs Vocabulary
    "amateurs" = people who are not professionals.
23. mistakes Vocabulary
    "make mistakes" (not "do").
24. people Vocabulary
    "several people": "people" is plural.
25. every Grammar
    "every image": "every" + singular noun.

## Tips for B2

- At B2 you meet the passive, relative clauses and linking words such as "however" or "although" more often.
- Watch the word class: adjective or adverb, noun or verb. The start of the word alone is often not enough.
- Keep to about 6 minutes per text, as in the University of Münster C-Test.

## More practice texts

**B1:** [The semester ticket](https://ctestprep.de/en/c-test-english-exercises/b1-the-semester-ticket) · [Volunteering in your free time](https://ctestprep.de/en/c-test-english-exercises/b1-volunteering-in-your-free-time) · [Food waste in the canteen](https://ctestprep.de/en/c-test-english-exercises/b1-food-waste-in-the-canteen)

**B2:** [How vaccines are tested](https://ctestprep.de/en/c-test-english-exercises/b2-how-vaccines-are-tested) · [Artificial light at night](https://ctestprep.de/en/c-test-english-exercises/b2-artificial-light-at-night)

**C1:** [The printing press](https://ctestprep.de/en/c-test-english-exercises/c1-the-printing-press) · [The economics of streaming](https://ctestprep.de/en/c-test-english-exercises/c1-the-economics-of-streaming) · [The decline of handwriting](https://ctestprep.de/en/c-test-english-exercises/c1-the-decline-of-handwriting)

[Three more texts (B1, B2, C1) on one page →](https://ctestprep.de/en/c-test-english-exercises)

**Ready for the real test?** The English Pass (€12) has 10 more texts and a simulation in the Münster format: 4 texts, 100 gaps, 25 minutes, with an estimated level. [See the Pass →](https://ctestprep.de/en/pricing)

[The C-Test at universities compared →](https://ctestprep.de/en/c-test-english)