1. I (am waiting) for the prices of the houses to come down before buying a
house, but I think I (have been waiting) too long and the prices are beginning to go
up again.
2. Call the children in! They (have been playing) outside since early morning and (have not done) their homework yet.
3. I'm afraid she (has not finished) typing those letters yet. She (has been dealing) with customers all morning.
4. You (have been fixing) this shelf for an hour. Let's ask Father to help you.
5. The students (have been translating) the article for 20 minutes but they (have not finished) it yet.