Explanation
The task is to complete the sentences using the present perfect continuous tense. This tense is used for actions that started in the past and are still continuing in the present. The structure is 'have/has been + verb-ing'.
Answer
- 1. He has been working here for over ten years.
- 2. Jill has been swimming in this lake since she was a child.
- 3. How long has this injured bird been? (Assuming 'have' is intended to be related to the bird's well-being or injury duration, this is the most logical completion given the context and tense).
- 4. They have been studying very hard for their exams.
- 5. My parents have been donating to WWF for a long time.
- 6. The government has been trying to reduce pollution for years.