III. Read the passage and choose the best answer.
1. C. with
2. A. gap
3. D. plan
4. B. population
5. C. early
IV. Read the text and answer the questions.
1. Young people of different nationalities go on International Young Pioneer Organisation expeditions.
2. There are ten expeditions every year.
3. Each expedition lasts for ten weeks.
4. The volunteers help scientists to do environmental research.
5. We must know English to become a volunteer.
