29.He turned down the request of his friend because it was________the limit of his power.
In the end I lost my ______ and shouted at her.
Lewis was much admired ______ his work on the advanced medical research.
The pilot, whether ______ or design, made the plane do a sharp turn.
If you ______ go, at least wait until the rain stops.
The reason for his success is ______ he worked very hard.